Clarified the necessity to use an app_main thread to take care of creating and starti...

[cmsis] / CMSIS / DoxyGen / RTOS2 / src / cmsis_os2.txt

/**
\page genRTOS2IF Generic RTOS Interface

CMSIS-RTOS2 is a generic API that is agnostic of the underlying RTOS kernel. Application programmers call CMSIS-RTOS2 API
functions in the user code to ensure maximum portability from one RTOS to another. Middleware using CMSIS-RTOS2 API takes
advantages of this approach by avoiding unnecessary porting efforts.

\image html "API_Structure.png" "CMSIS-RTOS API Structure"

A typical CMSIS-RTOS2 API implementation interfaces to an existing real-time kernel. The CMSIS-RTOS2 API provides the
following attributes and functionalities:
 - Function names, identifiers, and parameters are descriptive and easy to understand. The functions are powerful and
   flexible which reduces the number of functions exposed to the user. 
 - \ref CMSIS_RTOS_ThreadMgmt allows you to define, create, and control threads.
 - Interrupt Service Routines (ISR) can \ref CMSIS_RTOS_ISR_Calls "call some CMSIS-RTOS functions". When a CMSIS-RTOS
   function cannot be called from an ISR context, it rejects the invocation and returns an error code.
 - Three different event types support communication between multiple threads and/or ISR:
   - \ref CMSIS_RTOS_ThreadFlagsMgmt "Thread Flags": may be used to indicate specific conditions to a thread.
   - \ref CMSIS_RTOS_EventFlags "Event Flags": may be used to indicate events to a thread or ISR.
   - \ref CMSIS_RTOS_Message "Messages": can be sent to a thread or an ISR. Messages are buffered in a queue.
 - \ref CMSIS_RTOS_MutexMgmt and \ref CMSIS_RTOS_SemaphoreMgmt are incorporated.
 - CPU time can be scheduled with the following functionalities:
   - A \a timeout parameter is incorporated in many CMSIS-RTOS functions to avoid system lockup. When a timeout is specified,
     the system waits until a resource is available or an event occurs. While waiting, other threads are scheduled.
   - The \ref osDelay and \ref osDelayUntil functions put a thread into the \b WAITING state for a specified period of time.
   - The \ref osThreadYield provides co-operative thread switching and passes execution to another thread of the same
     priority.
 - \ref CMSIS_RTOS_TimerMgmt  functions are used to trigger the execution of functions.

The CMSIS-RTOS2 API is designed to optionally incorporate multi-processor systems and/or access protection via the Cortex-M
Memory Protection Unit (MPU).

In some RTOS implementations threads may execute on different processors, thus \b message queues may reside in shared memory
resources.

The CMSIS-RTOS2 API encourages the software industry to evolve existing RTOS implementations. RTOS implementations can be
different and optimized in various aspects towards the Cortex-M processors. Optional features may be for example
 - Support of the Cortex-M Memory Protection Unit (MPU).
 - Support of multi-processor systems.
 - Support of a DMA controller.
 - Deterministic context switching.
 - Round-robin context switching.
 - Deadlock avoidance, for example with priority inversion.
 - Zero interrupt latency by using Armv7-M instructions LDREX and STREX.

\section cmsis_os2_h cmsis_os2.h header file

The file \b %cmsis_os2.h is a standard header file that interfaces to every CMSIS-RTOS2 compliant real-time operating
systems (RTOS). Each implementation is provided the same \b cmsis_os2.h which defines the interface to the \ref rtos_api2.

Using the \b cmsis_os2.h along with dynamic object allocation allows to create source code or libraries that require no
modifications when using on a different CMSIS-RTOS2 implementation.

\section usingOS2 Using a CMSIS-RTOS2 Implementation

A CMSIS-RTOS2 component may be provided as library or source code (the picture below shows a library). 
A CMSIS-based application is extended with RTOS functionality by adding a CMSIS-RTOS2 component (and typically some configuration files).
The \ref cmsis_os2_h gives access to RTOS API functions and is the only interface header required when dynamic object allocation is used.
This enables portable application that works with every RTOS kernel event without re-compilation of the source code when the kernel is 
changed.

Static object allocation requires access to RTOS object control block definitions. An implementation specific header file (<i>rtos</i>.h in 
the picture below) provides access to such definitions. The section For RTX v5 these definitions are provided in the header file %rtx_os.h that contains this definitions for RTX v5.


\image html "CMSIS_RTOS_Files.png" "CMSIS-RTOS File Structure"

Once the files are added to a project, the user can start working with the CMSIS-RTOS functions.  A code example is provided
below:
 
<b>Code Example</b>
\code
/*----------------------------------------------------------------------------
 * CMSIS-RTOS 'main' function template
 *---------------------------------------------------------------------------*/
 
#include "RTE_Components.h"
#include  CMSIS_device_header
#include "cmsis_os2.h"
 
/*----------------------------------------------------------------------------
 * Application main thread
 *---------------------------------------------------------------------------*/
void app_main (void *argument) {
 
  // ...
  for (;;) {}
}
 
int main (void) {
 
  // System Initialization
  SystemCoreClockUpdate();
  // ...
 
  osKernelInitialize();                 // Initialize CMSIS-RTOS
  osThreadNew(app_main, NULL, NULL);    // Create application main thread
  osKernelStart();                      // Start thread execution
  for (;;) {}
}
\endcode


*/


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/**
\page rtx5_impl RTX v5 Implementation

Keil RTX version 5 (RTX5) implements the CMSIS-RTOS2 as a native RTOS interface for Arm Cortex-M processor-based devices.
A translation layer to CMSIS-RTOS API v1 is provided. Therefore, RTX5 can be used in applications that where previously based
on RTX version 4 and CMSIS-RTOS version 1 with minimal effort.

The following sections provide further details:
 - \subpage cre_rtx_proj explains how to setup an RTX v5 project in Keil MDK.
 - \subpage theory_of_operation provides general information about the operation of CMSIS-RTOS RTX v5.
 - \subpage config_rtx5 describes configuration parameters of CMSIS-RTOS RTX v5.
 - \subpage creating_RTX5_LIB explains how to build your own CMSIS-RTOS RTX v5 library.
 - \subpage technicalData5 lists hardware, software, and resource requirements, supplied files, and supported tool chains.
 - \subpage misraCompliance5 describes the violations to the MISRA standard.
*/

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/**
\page cre_rtx_proj Create an RTX5 Project

\if FuSaRTS
FuSa RTX5 installation and project setup are explained in \ref fusa_rtx_installation.

\endif

\ifnot FuSaRTS
The steps to create a microcontroller application using RTX5 are:
- Create a new project and select a microcontroller device.
- In the Manage Run-Time Environment window, select <b>CMSIS\::CORE</b> and <b>CMSIS\::RTOS2 (API)\::Keil RTX5</b>. You can
  choose to either add RTX as a library (Variant: \b Library) or to add the full source code (Variant: \b Source - required
  if using the <a href="http://www.keil.com/pack/doc/compiler/EventRecorder/html/index.html" target="_blank"><b>Event Recorder</b></a>):

   \image html manage_rte_output.png

- If the <b>Validation Output</b> requires other components to be present, try to use the \b Resolve button.
- Click \b OK. In the \b Project window, you will see the files that have been automatically added to you project, such as
  \b %RTX_Config.h, \b %RTX_Config.c, the library or the source code files, as well as the system and startup files:

   \image html project_window.png

- If using the Variant: \b Source as statet above, you have to assure to use at least C99 compiler mode (Project Options -> C/C++ -> C99 Mode).   
- You can add template files to the project by right-clicking on <b>Source Group 1</b> and selecting
  <b>Add New Item to 'Source Group 1'</b>. In the new window, click on <b>User Code Template</b>. On the right-hand side
  you will see all available template files for CMSIS-RTOS RTX:
  
   \image html add_item.png

- \ref config_rtx5 "Configure" RTX5 to the application's needs using the \b %RTX_Config.h file.

\endif

\if ARMCA \section cre_rtx_cortexa Additional requirements for RTX on Cortex-A

Cortex-A based microcontrollers are less unified with respect to the interrupt and timer implementations used compared to 
M-class devices. Thus RTX requires additional components when an A-class device is used, namely
<a href="../../Core_A/html/group__irq__ctrl__gr.html"><b>IRQ Controller (API)</b></a> and \ref CMSIS_RTOS_TickAPI "OS Tick (API)"
implementations. 

\image html manage_rte_cortex-a.png

The default implementations provided along with CMSIS are 
- Arm <a href="../../Core_A/html/group__GIC__functions.html">Generic Interrupt Controller (GIC)</a>
- Arm Cortex-A5, Cortex-A9 <a href="../../Core_A/html/group__PTM__timer__functions.html">Private Timer (PTIM)</a>
- Arm Cortex-A7 <a href="../../Core_A/html/group__PL1__timer__functions.html">Generic Physical Timer (GTIM)</a>

For devices not implementing GIC, PTIM nor GTIM please refer to the according device family pack and select the
proper implementations.

\endif

\section cre_UsingIRQs Using Interrupts on Cortex-M

On Cortex-M processors, the RTX5 kernel uses the following interrupt exceptions.  The table below also lists the 
priorities that must be assigned to these interrupts.

Handler | Priority | Interrupt/Exception
:-------|:---------|:----------------------------
SysTick | lowest   | Kernel system timer interrupt to generate periodic timer ticks
PendSV  | lowest   | PendSV (request for system-level service) when calling certain RTX functions from \b Handler mode
SVC     | lowest+1 | Supervisor Call used to enter the RTOS kernel from \b Thread mode

Other device interrupts can be used without limitation. For Arm Cortex-M3/M4/M7 \if ARMv8M /M23/M33/M35P \endif  processors, interrupts are never disabled by RTX Kernel.

<b>Usage of interrupt priority grouping</b>
- The interrupt priority grouping should be configured using the CMSIS-Core function NVIC_SetPriorityGrouping before calling the function 
  \ref osKernelStart(). The RTX kernel uses the priority group value to setup the priority for SysTick and PendSV interrupts.
- The RTX kernel sets the priority for the interrupts/exceptions listed in above table and uses the lowest two priority levels.
- Do not change the priority used by the RTX kernel. If this cannot be avoided, ensure that the preempt priority of
  SysTick/PendSV is lower than SVC.
- Permitted priority group values are 0 to 6. The priority group value 7 will cause RTX to fail as there is only one priority level available.
- The <b>main stack</b> is used to run the RTX functionality. It is therefore required to configure sufficient stack for the RTX kernel execution.

<b>Code Example</b>
\code
osKernelInitialize();                            // initialize RTX
NVIC_SetPriorityGrouping (3);                    // setup priority grouping
tread_id = osThreadNew(tread_func, NULL, NULL);  // create some threads
osKernelStart ();                                // start RTX kernel
\endcode

\section cre_rtx_proj_specifics Add support for RTX specific functions
If you require some of the \ref rtx5_specific "RTX specific functions" in your application code, \#include the
\ref rtx_os_h "header file rtx_os.h". This enables \ref lowPower "low-power" and \ref TickLess "tick-less" operation modes.

\section cre_rtx_proj_er Add Event Recorder Visibility

RTX5 interfaces to the <a href="http://www.keil.com/pack/doc/compiler/EventRecorder/html/index.html" target="_blank"><b>Event Recorder</b></a> 
to provide event information which helps you to understand and analyze the operation.

- To use the Event Recorder together with RTX5, select the software component <b>Compiler:Event Recorder</b>.
- Select the \b Source variant of the software component <b>CMSIS:RTOS2 (API):Keil RTX5</b>.
  \image html event_recorder_rte.png "Component selection for Event Recorder"
- Enable the related settings under \ref evtrecConfig.
- Build the application code and download it to the debug hardware.
  
Once the target application generates event information, it can be viewed in the µVision debugger using the \b Event \b Recorder.
*/


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/**
\page theory_of_operation Theory of Operation

Many aspects of the kernel are configurable and the configuration options are mentioned where applicable.

\section SystemStartup System Startup

Since main is no longer a thread RTX5 does not interfere with the system startup until main is reached.
Once the execution reaches \c main() there is a recommended order to initialize the hardware and start the kernel. This is
also reflected in the user code template file "CMSIS-RTOS2 'main' function" supplied with the RTX5 component.

Your application's \c main() should implement at least the following in the given order:
-# Initialization and configuration of hardware including peripherals, memory, pins, clocks and the interrupt system.
-# Update the system core clock using the respective
   <a href=../../Core/html/group__system__init__gr.html>CMSIS-Core (Cortex-M)</a>  \if ARMCA or <a href=../../Core_A/html/group__system__init__gr.html>CMSIS-Core (Cortex-A)</a> \endif function.
-# Initialize the CMSIS-RTOS kernel using \ref osKernelInitialize.
-# Optionally, create one thread (for example \c app_main), which is used as a main thread using \ref osThreadNew. This
   thread should take care of creating and starting objects, once it is run by the scheduler. Alternatively, threads can be
   created in \c main() directly.
-# Start the RTOS scheduler using \ref osKernelStart which also configures the system tick timer and initializes RTOS
   specific interrupts. This function does not return in case of successful execution. Therefore, any application code after
   \b osKernelStart will not be executed.

\note
- Modifying priorities and groupings in the NVIC by the application after the above sequence is not recommended.
- Before executing \ref osKernelStart, only the functions \ref osKernelGetInfo, \ref osKernelGetState, and object creation
  functions (osXxxNew) may be called.


\section Scheduler 

RTX5 implements a low-latency preemptive scheduler. Major parts of RTX5 are executed in handler mode such as
  - \ref SysTick_Handler used for time-based scheduling.
  - \ref SVC_Handler used for lock-based scheduling.
  - \ref PendSV_Handler used for interrupt-based scheduling.

In order to be low-latency with respect to ISR execution those system exceptions are configured to use the
lowest priority groups available. The priorities are configured such that no preemption happens between them. Thus
no interrupt critical sections (i.e. interrupt locks) are needed to protect the scheduler.

\image html scheduling.png "Thread scheduling and interrupt execution"

The scheduler combines priority and round-robin based context switches. The example depicted in the image above contains
four threads (1, 2, 3, and 4). Threads 1 and 2 share the same priority, thread 3 has a higher one and thread 4 the highest
(\ref osThreadAttr_t::priority). As long as threads 3 and 4 are blocked the scheduler switches between thread 1 and 2 on
a time-slice basis (round-robin). The time-slice for round-robin scheduling can be configured, see Round-Robin Timeout in \ref systemConfig.

Thread 2 unblocks thread 3 by an arbitrary RTOS-call (executed in SVC handler mode) at time index 2. The scheduler switches to
thread 3 immediately because thread 3 has the highest priority. Thread 4 is still blocked.

At time index 4 an interrupt (ISR) occurs and preempts the SysTick_Handler. RTX does not add any latency to the interrupt
service execution. The ISR routine uses an RTOS-call that unblocks thread 4. Instead of switching to thread 4 immediately
the PendSV flag is set to defer the context switching. The PendSV_Handler is executed right after the SysTick_Handler returns
and the deferred context switch to thread 4 is carried out. As soon as highest priority thread 4 blocks again by using
a blocking RTOS-call execution is switched back to thread 3 immediately during time index 5.

At time index 5 thread 3 uses a blocking RTOS-call as well. Thus the scheduler switches back to thread 2 for time index 6.
At time index 7 the scheduler uses the round-robin mechanism to switch to thread 1 and so on.

\section MemoryAllocation Memory Allocation 

RTX5 objects (thread, mutex, semaphore, timer, message queue, thread and event flags, as well as memory pool) require
dedicated RAM memory. Objects can be created using os<i>Object</i>New() calls and deleted using os<i>Object</i>Delete()
calls. The related object memory needs to be available during the lifetime of the object.

RTX5 offers three different memory allocation methods for objects:
  - \ref GlobalMemoryPool uses a single global memory pool for all objects. It is easy to configure, but may have 
    the disadvantage for memory fragmentation when objects with different sizes are created and destroyed.
  - \ref ObjectMemoryPool uses a fixed-size memory pool for each object type. The method is time deterministic
     and avoids memory fragmentation.
  - \ref StaticObjectMemory reserves memory during compile time and completely avoids that a system can be out of memory.
    This is typically a required for some safety critical systems.

It possible to intermix all the memory allocation methods in the same application.

\subsection GlobalMemoryPool Global Memory Pool

The global memory pool allocates all objects from a memory area. This method of memory allocation is the default
configuration setting of RTX5.

\image html MemAllocGlob.png "Global Memory Pool for all objects"

When the memory pool does not provide sufficient memory, the creation of the object fails and the related
os<i>Object</i>New() function returns \token{NULL}.

Enabled in \ref systemConfig.

\subsection ObjectMemoryPool Object-specific Memory Pools

Object-specific memory pools avoids memory fragmentation with a dedicated fixed-size memory management for each object type.
This type of memory pools are fully time deterministic, which means that object creation and destruction takes always the
same fixed amount of time. As a fixed-size memory pool is specific to an object type, the handling of out-of-memory
situations is simplified.

\image html MemAllocSpec.png "One memory pool per object type"

Object-specific memory pools are selectively enabled for each object type, e.g: mutex or thread using the RTX configuration
file:
 - Enabled in \ref threadConfig for thread objects.
 - Enabled in \ref timerConfig for timer objects.
 - Enabled in \ref eventFlagsConfig for event objects.
 - Enabled in \ref mutexConfig for mutex objects.
 - Enabled in \ref semaphoreConfig for semaphore.
 - Enabled in \ref memPoolConfig for memory pools.
 - Enabled in \ref msgQueueConfig for message objects.

When the memory pool does not provide sufficient memory, the creation of the object fails and the related
os<i>Object</i>New() function returns \token{NULL}.

\subsection StaticObjectMemory Static Object Memory
In contrast to the dynamic memory allocations, the static memory allocation requires compile-time allocation of object memory. 

\image html MemAllocStat.png "Statically allocated memory for all objects"

Static memory allocation can be achieved by providing user-defined memory using attributes at object creation,
see \ref CMSIS_RTOS_MemoryMgmt_Manual. Please take special note of the following restrictions:

Memory type                                  | Requirements
---------------------------------------------|-------------------------------------------------------------------------------
Control Block (osXxxAttr_t::cb_mem)          | 4-Byte alignment. Size defined by \ref osRtxThreadCbSize, \ref osRtxTimerCbSize, \ref osRtxEventFlagsCbSize, \ref osRtxMutexCbSize, \ref osRtxSemaphoreCbSize, \ref osRtxMemoryPoolCbSize, \ref osRtxMessageQueueCbSize.
Thread Stack (osThreadAttr_t::stack_mem)     | 8-Byte alignment. Size is application specific, i.e. amount of stack variables and frames.
Memory Pool (osMemoryPoolAttr_t::mp_mem)     | 4-Byte alignment. Size calculated with \ref osRtxMemoryPoolMemSize.
Message Queue (osMessageQueueAttr_t::mq_mem) | 4-Byte alignment. Size calculated with \ref osRtxMessageQueueMemSize.


In order to allow RTX5 aware debugging, i.e. Component Viewer, to recognize control blocks these
needs to be placed in individual memory sections, i.e. using `__attribute__((section(...)))`.

RTX Object    | Linker Section 
--------------|------------------------
Thread        | `.bss.os.thread.cb`
Timer         | `.bss.os.timer.cb`
Event Flags   | `.bss.os.evflags.cb`
Mutex         | `.bss.os.mutex.cb`
Semaphore     | `.bss.os.semaphore.cb`
Memory Pool   | `.bss.os.mempool.cb`
Message Queue | `.bss.os.msgqueue.cb`

The following code example shows how to create an OS object using static memory.

<b> Code Example:</b> 
\code{.c}
/*----------------------------------------------------------------------------
 * CMSIS-RTOS 'main' function template
 *---------------------------------------------------------------------------*/

#include "RTE_Components.h"
#include  CMSIS_device_header
#include "cmsis_os2.h"
 
//include rtx_os.h for types of RTX objects
#include "rtx_os.h"
 
//The thread function instanced in this example
void worker(void *arg)
{
  while(1) 
  {
    //work
    osDelay(10000);
  }  
}
 
// Define objects that are statically allocated for worker thread 1
__attribute__((section(".bss.os.thread.cb")))
osRtxThread_t worker_thread_tcb_1;
 
// Reserve two areas for the stacks of worker thread 1
// uint64_t makes sure the memory alignment is 8
uint64_t worker_thread_stk_1[64];
 
// Define the attributes which are used for thread creation
// Optional const saves RAM memory and includes the values in periodic ROM tests 
const osThreadAttr_t worker_attr_1 = {
  "wrk1",
  osThreadJoinable,
  &worker_thread_tcb_1,
  sizeof(worker_thread_tcb_1),
  &worker_thread_stk_1[0],
  sizeof(worker_thread_stk_1),
  osPriorityAboveNormal,
  0
};
 
// Define ID object for thread
osThreadId_t th1;
 
/*----------------------------------------------------------------------------
 * Application main thread
 *---------------------------------------------------------------------------*/
void app_main (void *argument) {
  uint32_t param = NULL;
 
  // Create an instance of the worker thread with static resources (TCB and stack)
  th1 = osThreadNew(worker, &param, &worker_attr_1);
 
  for (;;) {}
}
 
int main (void) {
  // System Initialization
  SystemCoreClockUpdate();
  // ...

  osKernelInitialize();                 // Initialize CMSIS-RTOS
  osThreadNew(app_main, NULL, NULL);    // Create application main thread
  osKernelStart();                      // Start thread execution
  for (;;) {}
}
\endcode


\section ThreadStack Thread Stack Management

For Cortex-M processors without floating point unit the thread context requires 64 bytes on the local stack.

\note For Cortex-M4/M7 with FP the thread context requires 200 bytes on the local stack. For these devices the default stack
space should be increased to a minimum of 300 bytes.

Each thread is provided with a separate stack that holds the thread context and stack space for automatic variables and
return addresses for function call nesting. The stack sizes of RTX threads are flexibly configurable as explained in the
section \ref threadConfig. RTX offers a configurable checking for stack overflows and stack utilization. 


\section lowPower Low-Power Operation

The system thread \b osRtxIdleThread can be use to switch the system into a low-power mode. The easiest form to enter a
low-power mode is the execution of the \c __WFE function that puts the processor into a sleep mode where it waits for an
event.

<b>Code Example:</b>
\code
#include "RTE_Components.h"
#include CMSIS_device_header            /* Device definitions                 */
 
void osRtxIdleThread (void) {
  /* The idle demon is a system thread, running when no other thread is       */
  /* ready to run.                                                            */
 
  for (;;) {
    __WFE();                            /* Enter sleep mode                   */
  }
}
\endcode

\note
\c __WFE() is not available in every Cortex-M implementation. Check device manuals for availability.


\section kernelTimer RTX Kernel Timer Tick

RTX uses the generic \ref CMSIS_RTOS_TickAPI to configure and control its periodic Kernel Tick.

To use an alternative timer as the Kernel Tick Timer one simply needs to implement a custom version
of the \ref CMSIS_RTOS_TickAPI.

\note The OS Tick implementation provided must asure that the used timer interrupt uses the same (low) priority group 
as the service interrupts, i.e. interrupts used by RTX must not preempt each other. Refer to the \ref Scheduler section
for more details.

\subsection TickLess Tick-less Low-Power Operation

RTX5 provides extension for tick-less operation which is useful for applications that use extensively low-power modes where
the SysTick timer is also disabled. To provide a time-tick in such power-saving modes, a wake-up timer is used to
derive timer intervals. The CMSIS-RTOS2 functions \ref osKernelSuspend and \ref osKernelResume control the tick-less
operation.

Using this functions allows the RTX5 thread scheduler to stop the periodic kernel tick interrupt. When all active threads
are suspended, the system enters power-down and calculates how long it can stay in this power-down mode. In the power-down
mode the processor and peripherals can be switched off. Only a wake-up timer must remain powered, because this timer is
responsible to wake-up the system after the power-down period expires.

The tick-less operation is controlled from the \b osRtxIdleThread thread. The wake-up timeout value is set before the system
enters the power-down mode. The function \ref osKernelSuspend calculates the wake-up timeout measured in RTX Timer Ticks;
this value is used to setup the wake-up timer that runs during the power-down mode of the system.

Once the system resumes operation (either by a wake-up time out or other interrupts) the RTX5 thread scheduler is started
with the function \ref osKernelResume. The parameter \a sleep_time specifies the time (in RTX Timer Ticks) that the system
was in power-down mode.

<b>Code Example:</b>
\code
#include "msp.h"                        // Device header

/*----------------------------------------------------------------------------
 *      MSP432 Low-Power Extension Functions
 *---------------------------------------------------------------------------*/
static void MSP432_LP_Entry(void) {
  /* Enable PCM rude mode, which allows to device to enter LPM3 without waiting for peripherals */
  PCM->CTL1 = PCM_CTL1_KEY_VAL | PCM_CTL1_FORCE_LPM_ENTRY;       
  /* Enable all SRAM bank retentions prior to going to LPM3  */
  SYSCTL->SRAM_BANKRET |= SYSCTL_SRAM_BANKRET_BNK7_RET;
  __enable_interrupt();
  NVIC_EnableIRQ(RTC_C_IRQn);
  /* Do not wake up on exit from ISR */
  SCB->SCR |= SCB_SCR_SLEEPONEXIT_Msk;
  /* Setting the sleep deep bit */
  SCB->SCR |= (SCB_SCR_SLEEPDEEP_Msk);  
}
 
static volatile unsigned int tc;
static volatile unsigned int tc_wakeup;
 
void RTC_C_IRQHandler(void)
{
  if (tc++ > tc_wakeup) 
  {
    SCB->SCR &= ~SCB_SCR_SLEEPONEXIT_Msk;    
    NVIC_DisableIRQ(RTC_C_IRQn);
    NVIC_ClearPendingIRQ(RTC_C_IRQn);
    return;
  }
  if (RTC_C->PS0CTL & RTC_C_PS0CTL_RT0PSIFG)
  {
    RTC_C->CTL0 = RTC_C_KEY_VAL;                 // Unlock RTC key protected registers
    RTC_C->PS0CTL &= ~RTC_C_PS0CTL_RT0PSIFG;
    RTC_C->CTL0 = 0;
    SCB->SCR |= (SCB_SCR_SLEEPDEEP_Msk);
  }
}
 
uint32_t g_enable_sleep = 0;
  
void osRtxIdleThread (void) {
  
  for (;;) {
    tc_wakeup = osKernelSuspend();
    /* Is there some time to sleep? */
    if (tc_wakeup > 0) {
      tc = 0;
      /* Enter the low power state */
      MSP432_LP_Entry();
      __WFE();
    }
    /* Adjust the kernel ticks with the amount of ticks slept */
    osKernelResume (tc);
  }
}
\endcode

\note
\c __WFE() is not available in every Arm Cortex-M implementation. Check device manuals for availability. 
The alternative using \c __WFI() has other issues, please take note of http://www.keil.com/support/docs/3591.htm as well.

\section rtx_os_h RTX5 Header File

Every implementation of the CMSIS-RTOS2 API can bring its own additional features. RTX5 adds a couple of
\ref rtx5_specific "functions" for the idle more, for error notifications, and special system timer functions. It also is
using macros for control block and memory sizes.

If you require some of the RTX specific functions in your application code, \#include the header file \b %rtx_os.h:

\include rtx_os.h


\section CMSIS_RTOS_TimeOutValue Timeout Value   

Timeout values are an argument to several \b osXxx functions to allow time for resolving a request. A timeout value of \b 0
means that the RTOS does not wait and the function returns instantly, even when no resource is available. A timeout value of
\ref osWaitForever means that the RTOS waits infinitely until a resource becomes available. Or one forces the thread to resume
using \ref osThreadResume which is discouraged.
 
The timeout value specifies the number of timer ticks until the time delay elapses. The value is an upper bound and 
depends on the actual time elapsed since the last timer tick. 

Examples:
  - timeout value \b 0 : the system does not wait, even when no resource is available the RTOS function returns instantly. 
  - timeout value \b 1 : the system waits until the next timer tick occurs; depending on the previous timer tick, it may be a
    very short wait time.
  - timeout value \b 2 : actual wait time is between 1 and 2 timer ticks.
  - timeout value \ref osWaitForever : system waits infinite until a resource becomes available. 
  
\image html TimerValues.png "Example of timeout using osDelay()"


\section CMSIS_RTOS_ISR_Calls Calls from Interrupt Service Routines 

The following CMSIS-RTOS2 functions can be called from threads and Interrupt Service Routines (ISR):
  - \ref osKernelGetInfo, \ref osKernelGetState,
    \ref osKernelGetTickCount, \ref osKernelGetTickFreq, \ref osKernelGetSysTimerCount, \ref osKernelGetSysTimerFreq
  - \ref osThreadGetId, \ref osThreadFlagsSet
  - \ref osEventFlagsSet, \ref osEventFlagsClear, \ref osEventFlagsGet, \ref osEventFlagsWait
  - \ref osSemaphoreAcquire, \ref osSemaphoreRelease, \ref osSemaphoreGetCount
  - \ref osMemoryPoolAlloc, \ref osMemoryPoolFree, \ref osMemoryPoolGetCapacity, \ref osMemoryPoolGetBlockSize,
    \ref osMemoryPoolGetCount, \ref osMemoryPoolGetSpace
  - \ref osMessageQueuePut, \ref osMessageQueueGet, \ref osMessageQueueGetCapacity, \ref osMessageQueueGetMsgSize,
    \ref osMessageQueueGetCount, \ref osMessageQueueGetSpace

Functions that cannot be called from an ISR are verifying the interrupt status and return the status code \b osErrorISR, in
case they are called from an ISR context. In some implementations, this condition might be caught using the HARD_FAULT
vector.
*/

/*=======0=========1=========2=========3=========4=========5=========6=========7=========8=========9=========0=========1====*/
/**
\page config_rtx5 Configure RTX v5

The file "RTX_Config.h" defines the configuration parameters of CMSIS-RTOS RTX and must be part of every project that is
using the CMSIS-RTOS RTX kernel. The configuration options are explained in detail in the following sections:
- \ref systemConfig covers system-wide settings for the global memory pool, tick frequency, ISR event buffer and round-robin thread switching.
- \ref threadConfig provides several parameters to configure the \ref CMSIS_RTOS_ThreadMgmt functions.
- \ref timerConfig provides several parameters to configure the \ref CMSIS_RTOS_TimerMgmt functions.
- \ref eventFlagsConfig provides several parameters to configure the \ref CMSIS_RTOS_EventFlags functions.
- \ref mutexConfig provides several parameters to configure the \ref CMSIS_RTOS_MutexMgmt functions.
- \ref semaphoreConfig provides several parameters to configure the \ref CMSIS_RTOS_SemaphoreMgmt functions.
- \ref memPoolConfig provides several parameters to configure the \ref CMSIS_RTOS_PoolMgmt functions.
- \ref msgQueueConfig provides several parameters to configure the \ref CMSIS_RTOS_Message functions.
- \ref evtrecConfig provides several parameters to configure RTX for usage with <a href="http://www.keil.com/pack/doc/compiler/EventRecorder/html/index.html" target="_blank"><b>Event Recorder</b></a>.

The file "RTX_Config.c" contains default implementations of the functions \ref osRtxIdleThread and \ref osRtxErrorNotify. Both functions
can simply be overwritten with a customized behavior by redefining them as part of the user code.

The configuration file uses <b>Configuration Wizard Annotations</b>. Refer to <b>Pack - Configuration Wizard Annotations</b> for details.
Depending on the development tool, the annotations might lead to a more user-friendly graphical representation of the
settings. The picture below shows the µVision \b Configuration \b Wizard view in MDK:

\image html config_wizard.png "RTX_Config.h in Configuration Wizard View"

Alternatively one can provide configuration options using the compiler command line.

For example one can customize the used tick frequency to 100us by (overwriting) the configuration using
\code
cc -DOS_TICK_FREQ=100
\endcode

\section systemConfig System Configuration

The system configuration covers system-wide settings for the global memory pool, tick frequency, ISR event buffer and
round-robin thread switching.

<b>System Configuration Options</b>
\image html config_wizard_system.png "RTX_Config.h: System Configuration"

Name                                   | \#define                 | Description
---------------------------------------|--------------------------|----------------------------------------------------------------
Global Dynamic Memory size [bytes]     | \c OS_DYNAMIC_MEM_SIZE   | Defines the combined global dynamic memory size for the \ref GlobalMemoryPool. Default value is \token{4096}. Value range is \token{[0-1073741824]} bytes, in multiples of \token{8} bytes.
Kernel Tick Frequency (Hz)             | \c OS_TICK_FREQ          | Defines base time unit for delays and timeouts in Hz. Default: 1000Hz = 1ms period.
Round-Robin Thread switching           | \c OS_ROBIN_ENABLE       | Enables Round-Robin Thread switching.
Round-Robin Timeout                    | \c OS_ROBIN_TIMEOUT      | Defines how long a thread will execute before a thread switch. Default value is \token{5}. Value range is \token{[1-1000]}.
ISR FIFO Queue                         | \c OS_ISR_FIFO_QUEUE     | RTOS Functions called from ISR store requests to this buffer. Default value is \token{16 entries}. Value range is \token{[4-256]} entries in multiples of \token{4}.
Object Memory usage counters           | \c OS_OBJ_MEM_USAGE      | Enables object memory usage counters to evaluate the maximum memory pool requirements individually for each RTOS object type.

\subsection systemConfig_glob_mem Global dynamic memory
Refer to \ref GlobalMemoryPool.


\subsection systemConfig_rr Round-Robin Thread Switching

RTX5 may be configured to use round-robin multitasking thread switching. Round-robin allows quasi-parallel execution of
several threads of the \a same priority. Threads are not really executed concurrently, but are scheduled where the available
CPU time is divided into time slices and RTX5 assigns a time slice to each thread. Because the time slice is typically short
(only a few milliseconds), it appears as though threads execute simultaneously.

Round-robin thread switching functions as follows:
- the tick is preloaded with the timeout value when a thread switch occurs
- the tick is decremented (if not already zero) each system tick if the same thread is still executing
- when the tick reaches 0 it indicates that a timeout has occurred. If there is another thread ready with the \a same
  priority, then the system switches to that thread and the tick is preloaded with timeout again.

In other words, threads execute for the duration of their time slice (unless a thread's time slice is given up). Then, RTX
switches to the next thread that is in \b READY state and has the same priority. If no other thread with the same priority is
ready to run, the current running thread resumes it execution.

\note When switching to higher priority threads, the round-robin timeout value is reset.

Round-Robin multitasking is controlled with the <b>\#define OS_ROBIN_ENABLE</b>. The time slice period is configured (in RTX
timer ticks) with the <b>\#define OS_ROBIN_TIMEOUT</b>.


\subsection systemConfig_isr_fifo ISR FIFO Queue
The RTX functions (\ref CMSIS_RTOS_ISR_Calls), when called from and interrupt handler, store the request type and optional
parameter to the ISR FIFO queue buffer to be processed later, after the interrupt handler exits.

The scheduler is activated immediately after the IRQ handler has finished its execution to process the requests stored to the
FIFO queue buffer. The required size of this buffer depends on the number of functions that are called within the interrupt
handler. An insufficient queue size will be caught by \b osRtxErrorNotify with error code \b osRtxErrorISRQueueOverflow.


\subsection systemConfig_usage_counters Object Memory Usage Counters

Object memory usage counters help to evaluate the maximum memory pool requirements for each object type, just like stack
watermarking does for threads. The initial setup starts with a global memory pool for all object types. Consecutive runs of
the application with object memory usage counters enabled, help to introduce object specific memory pools for each object
type. Normally, this is required for applications that require a functional safety certification as global memory pools are
not allowed in this case.


\section threadConfig Thread Configuration

The RTX5 provides several parameters to configure the \ref CMSIS_RTOS_ThreadMgmt functions.

<b>Thread Configuration Options</b>
\image html config_wizard_threads.png "RTX_Config.h: Thread Configuration"

<br> 
Option                                                   | \#define               | Description
:--------------------------------------------------------------------------|:-------------------------------|:---------------------------------------------------------------
Object specific Memory allocation                        | \c OS_THREAD_OBJ_MEM   | Enables object specific memory allocation. See \ref ObjectMemoryPool.
Number of user Threads                                   | \c OS_THREAD_NUM       | Defines maximum number of user threads that can be active at the same time. Applies to user threads with system provided memory for control blocks. Default value is \token{1}. Value range is \token{[1-1000]}.
Number of user Threads with default Stack size  | \c OS_THREAD_DEF_STACK_NUM     | Defines maximum number of user threads with default stack size and applies to user threads with \token{0} stack size specified. Value range is \token{[0-1000]}.
Total Stack size [bytes] for user Threads with user-provided Stack size    | \c OS_THREAD_USER_STACK_SIZE | Defines the combined stack size for user threads with user-provided stack size. Default value is \token{0}. Value range is \token{[0-1073741824]} Bytes, in multiples of \token{8}. 
Default Thread Stack size [bytes]                        | \c OS_STACK_SIZE    | Defines stack size for threads with zero stack size specified. Default value is \token{200}. Value range is \token{[96-1073741824]} Bytes, in multiples of \token{8}. 
Idle Thread Stack size [bytes]                           | \c OS_IDLE_THREAD_STACK_SIZE              | Defines stack size for Idle thread. Default value is \token{200}. Value range is \token{[72-1073741824]} bytes, in multiples of \token{8}. 
Idle Thread TrustZone Module ID                                            | \c OS_IDLE_THREAD_TZ_MOD_ID    | Defines the \ref osThreadAttr_t::tz_module "TrustZone Module ID" the Idle Thread shall use. This needs to be set to a non-zero value if the Idle Thread need to call secure functions. Default value is \token{0}.
Stack overrun checking                                   | \c OS_STACK_CHECK   | Enable stack overrun checks at thread switch. 
Stack usage watermark                                    | \c OS_STACK_WATERMARK    | Initialize thread stack with watermark pattern for analyzing stack usage. Enabling this option increases significantly the execution time of thread creation.
Processor mode for Thread execution                      | \c OS_PRIVILEGE_MODE     | Controls the processor mode. Default value is \token{Privileged} mode. Value range is \token{[0=Unprivileged; 1=Privileged]} mode.

\subsection threadConfig_countstack Configuration of Thread Count and Stack Space

The RTX5 kernel uses a separate stack space for each thread and provides two methods for defining the stack requirements:
 - <b>Static allocation</b>: when \ref osThreadAttr_t::stack_mem and \ref osThreadAttr_t::stack_size specify a memory area
   which is used for the thread stack. \b Attention: The stack memory provided must be 64-bit aligned, i.e. by using uint64_t for declaration.
 - <b>Dynamic allocation</b>: when \ref osThreadAttr_t is NULL or \ref osThreadAttr_t::stack_mem is NULL, the system
   allocates the stack memory from:
     - Object-specific Memory Pool (default Stack size) when "Object specific Memory allocation" is enabled and "Number of
       user Threads with default Stack size" is not \token{0} and \ref osThreadAttr_t::stack_size is \token{0} (or
       \ref osThreadAttr_t is NULL).
     - Object-specific Memory Pool (user-provided Stack size) when "Object specific Memory allocation" is enabled and "Total
       Stack size for user..."  is not \token{0} and \ref osThreadAttr_t::stack_size is not \token{0}.
     - Global Memory Pool when "Object specific Memory allocation" is disabled or (\ref osThreadAttr_t::stack_size is not
       \token{0} and "Total Stack size for user..." is \token{0}) or (\ref osThreadAttr_t::stack_size is \token{0} and
       "Number of user Threads with default Stack size" is \token{0}).

\ref osThreadAttr_t is a parameter of the function \ref osThreadNew.

\note
Before the RTX kernel is started by the \ref osKernelStart() function, the main stack defined in startup_<i>device</i>.s is
used. The main stack is also used for:
 - user application calls to RTX functions in \b thread \b mode using SVC calls
 - interrupt/exception handlers.
 
\subsection threadConfig_ovfcheck Stack Overflow Checking
RTX5 implements a software stack overflow checking that traps stack overruns. Stack is used for return addresses and
automatic variables. Extensive usage or incorrect stack configuration may cause a stack overflow. Software stack overflow
checking is controlled with the define \c OS_STACK_CHECK.
 
If a stack overflow is detected, the function \ref osRtxErrorNotify with error code \ref osRtxErrorStackUnderflow is called. By
default, this function is implemented as an endless loop and will practically stop code execution.

\subsection threadConfig_watermark Stack Usage Watermark
RTX5 initializes thread stack with a watermark pattern (0xCC) when a thread is created. This allows the debugger to determine
the maximum stack usage for each thread. It is typically used during development but removed from the final application.
Stack usage watermark is controlled with the define \c OS_STACK_WATERMARK.
  
Enabling this option significantly increases the execution time of \ref osThreadNew (depends on thread stack size).
 
\subsection threadConfig_procmode Processor Mode for Thread Execution
RTX5 allows to execute threads in unprivileged or privileged processor mode. The processor mode is controlled with the
define \c OS_PRIVILEGE_MODE.
 
In \b unprivileged processor mode, the application software:
- has limited access to the MSR and MRS instructions, and cannot use the CPS instruction.
- cannot access the system timer, NVIC, or system control block.
- might have restricted access to memory or peripherals.

In \b privileged processor mode, the application software can use all the instructions and has access to all resources.


\section timerConfig Timer Configuration

RTX5 provides several parameters to configure the \ref CMSIS_RTOS_TimerMgmt functions.

<b>Timer Configuration Options</b>
\image html config_wizard_timer.png "RTX_Config.h: Timer Configuration"

Name                                   | \#define                 | Description
---------------------------------------|--------------------------------|----------------------------------------------------------------
Object specific Memory allocation      | \c OS_TIMER_OBJ_MEM      | Enables object specific memory allocation. 
Number of Timer objects                | \c OS_TIMER_NUM          | Defines maximum number of objects that can be active at the same time. Applies to objects with system provided memory for control blocks. Value range is \token{[1-1000]}.
Timer Thread Priority                  | \c OS_TIMER_THREAD_PRIO        | Defines priority for timer thread. Default value is \token{40}. Value range is \token{[8-48]}, in multiples of \token{8}. The numbers have the following priority correlation: \token{8=Low}; \token{16=Below Normal}; \token{24=Normal}; \token{32=Above Normal}; \token{40=High}; \token{48=Realtime} 
Timer Thread Stack size [bytes]        | \c OS_TIMER_THREAD_STACK_SIZE  | Defines stack size for Timer thread. May be set to 0 when timers are not used. Default value is \token{200}. Value range is \token{[0-1073741824]}, in multiples of \token{8}.
Timer Thread TrustZone Module ID       | \c OS_TIMER_THREAD_TZ_MOD_ID   | Defines the \ref osThreadAttr_t::tz_module "TrustZone Module ID" the Timer Thread shall use. This needs to be set to a non-zero value if any Timer Callbacks need to call secure functions. Default value is \token{0}.
Timer Callback Queue entries           | \c OS_TIMER_CB_QUEUE           | Number of concurrent active timer callback functions. May be set to 0 when timers are not used. Default value is \token{4}. Value range is \token{[0-256]}.

\subsection timerConfig_obj Object-specific memory allocation
See \ref ObjectMemoryPool.

\subsection timerConfig_user User Timer Thread
The RTX5 function \b osRtxTimerThread executes callback functions when a time period expires. The priority of the timer
subsystem within the complete RTOS system is inherited from the priority of the \b osRtxTimerThread. This is configured by
\c OS_TIMER_THREAD_PRIO. Stack for callback functions is supplied by \b osRtxTimerThread. \c OS_TIMER_THREAD_STACK_SIZE must
satisfy the stack requirements of the callback function with the highest stack usage. 


\section eventFlagsConfig Event Flags Configuration

RTX5 provides several parameters to configure the \ref CMSIS_RTOS_EventFlags functions.

<b>Event Configuration Options</b>
\image html config_wizard_eventFlags.png "RTX_Config.h: Event Flags Configuration"

Name                                   | \#define                 | Description
---------------------------------------|--------------------------|----------------------------------------------------------------
Object specific Memory allocation      | \c OS_EVFLAGS_OBJ_MEM    | Enables object specific memory allocation. See \ref ObjectMemoryPool.
Number of Event Flags objects          | \c OS_EVFLAGS_NUM        | Defines maximum number of objects that can be active at the same time. Applies to objects with system provided memory for control blocks. Value range is \token{[1-1000]}.

\subsection eventFlagsConfig_obj Object-specific memory allocation
When object-specific memory is used, the pool size for all Event objects is specified by \c OS_EVFLAGS_NUM. Refer to
\ref ObjectMemoryPool.


\section mutexConfig Mutex Configuration
RTX5 provides several parameters to configure the \ref CMSIS_RTOS_MutexMgmt functions.

<b>Mutex Configuration Options</b>
\image html config_wizard_mutex.png "RTX_Config.h: Mutex Configuration"


Name                                   | \#define                 | Description
---------------------------------------|--------------------------|----------------------------------------------------------------
Object specific Memory allocation      | \c OS_MUTEX_OBJ_MEM      | Enables object specific memory allocation. See \ref ObjectMemoryPool.
Number of Mutex objects                | \c OS_MUTEX_NUM          | Defines maximum number of objects that can be active at the same time. Applies to objects with system provided memory for control blocks. Value range is \token{[1-1000]}.

\subsection mutexConfig_obj Object-specific Memory Allocation
When object-specific memory is used, the pool size for all Mutex objects is specified by \c OS_MUTEX_NUM. Refer to
\ref ObjectMemoryPool.


\section semaphoreConfig Semaphore Configuration

RTX5 provides several parameters to configure the \ref CMSIS_RTOS_SemaphoreMgmt functions.

<b>Semaphore Configuration Options</b>
\image html config_wizard_semaphore.png "RTX_Config.h: Semaphore Configuration"


Name                                   | \#define                 | Description
---------------------------------------|--------------------------|----------------------------------------------------------------
Object specific Memory allocation      | \c OS_SEMAPHORE_OBJ_MEM  | Enables object specific memory allocation. See \ref ObjectMemoryPool.
Number of Semaphore objects            | \c OS_SEMAPHORE_NUM      | Defines maximum number of objects that can be active at the same time. Applies to objects with system provided memory for control blocks. Value range is \token{[1-1000]}.

\subsection semaphoreConfig_obj Object-specific memory allocation
When Object-specific Memory is used, the pool size for all Semaphore objects is specified by \c OS_SEMAPHORE_NUM. Refer to
\ref ObjectMemoryPool.


\section memPoolConfig Memory Pool Configuration

RTX5 provides several parameters to configure the \ref CMSIS_RTOS_PoolMgmt functions.

<b>Memory Pool Configuration Options</b>
\image html config_wizard_memPool.png "RTX_Config.h: Memory Pool Configuration"

Name                                   | \#define                 | Description
---------------------------------------|--------------------------|----------------------------------------------------------------
Object specific Memory allocation      | \c OS_MEMPOOL_OBJ_MEM    | Enables object specific memory allocation. See \ref ObjectMemoryPool.
Number of Memory Pool objects          | \c OS_MEMPOOL_NUM        | Defines maximum number of objects that can be active at the same time. Applies to objects with system provided memory for control blocks. Value range is \token{[1-1000]}.
Data Storage Memory size [bytes]       | \c OS_MEMPOOL_DATA_SIZE  | Defines the combined data storage memory size. Applies to objects with system provided memory for data storage. Default value is \token{0}. Value range is \token{[0-1073741824]}, in multiples of \token{8}.

\subsection memPoolConfig_obj Object-specific memory allocation
When object-specific memory is used, the number of pools for all MemoryPool objects is specified by \c OS_MEMPOOL_NUM. The
total storage size reserved for all pools is configured in \c OS_MEMPOOL_DATA_SIZE. Refer to \ref ObjectMemoryPool.


\section msgQueueConfig Message Queue Configuration

RTX5 provides several parameters to configure the \ref CMSIS_RTOS_Message functions.

<b>MessageQueue Configuration Options</b>
\image html config_wizard_msgQueue.png "RTX_Config.h: Message Queue Configuration"

Name                                   | \#define                 | Description
---------------------------------------|--------------------------|----------------------------------------------------------------
Object specific Memory allocation      | \c OS_MSGQUEUE_OBJ_MEM   | Enables object specific memory allocation. See \ref ObjectMemoryPool.
Number of Message Queue objects        | \c OS_MSGQUEUE_NUM       | Defines maximum number of objects that can be active at the same time. Applies to objects with system provided memory for control blocks. Value range is \token{[1-1000]}.
Data Storage Memory size [bytes]       | \c OS_MSGQUEUE_DATA_SIZE | Defines the combined data storage memory size. Applies to objects with system provided memory for data storage. Default value is \token{0}. Value range is \token{[0-1073741824]}, in multiples of \token{8}.

\subsection msgQueueConfig_obj Object-specific memory allocation
When Object-specific Memory is used, the number of queues for all Message Queue objects is specified by \c OS_MSGQUEUE_NUM.
The total storage size reserved for all queues is configured in \c OS_MSGQUEUE_DATA_SIZE. Refer to \ref ObjectMemoryPool.


\section evtrecConfig Event Recorder Configuration

This section describes the configuration settings for the <a href="http://www.keil.com/pack/doc/compiler/EventRecorder/html/index.html" target="_blank">Event Recorder</a>
annotations. The usage requires the source variant of RTX5; refer to \ref cre_rtx_proj_er for more information.

\subsection evtrecConfigGlobIni Global Configuration
Initialize Event Recorder during the \ref osKernelInitialize and optionally start event recording.

\image html config_wizard_evtrecGlobIni.png "RTX_Config.h: Global Configuration"

<br/>

Name                  | \#define        | Description
----------------------|-----------------|----------------------------------------------------------------
Global Initialization | \c OS_EVR_INIT  | Initialize Event Recorder during \ref osKernelInitialize.
Start Recording       | \c OS_EVR_START | Start event recording after initialization.

\note
- If <b>Global Initialization (\c OS_EVR_INIT)</b> is set, an explicit call to \c EventRecorderInitialize is not required.
- If <b>Start Recording (\c OS_EVR_START)</b> is set, an explicit call to \c EventRecorderStart is not required. You may call the function \c EventRecorderStop to stop recording.


<b>Global Event Filter Setup</b>

These event filter settings are applied to all software component numbers, including MDK middleware and user components.

\image html config_wizard_evtrecGlobEvtFiltSetup.png "RTX_Config.h: Global Event Filter Setup"

<br/>

Name                      | \#define         | Description
--------------------------|------------------|----------------------------------------------------------------
Error events              | \c OS_EVR_LEVEL  | Enable error events.
API function call events  | \c OS_EVR_LEVEL  | Enable API function call events.
Operation events          | \c OS_EVR_LEVEL  | Enable operation events.
Detailed operation events | \c OS_EVR_LEVEL  | Enable detailed operation events.

\note
You may disable event recording for specific software components by calling the function \c EventRecorderDisable.

<b>RTOS Event Filter Setup</b>

These event filter settings are applied to specific RTX component groups with sub-options for:
- Error events
- API function call events
- Operation events
- Detailed operation events

The generation of events must be enabled as explained under \ref evtrecConfigEvtGen.


\image html config_wizard_evtrecRTOSEvtFilterSetup.png "RTX_Config.h: RTOS Event Filter Setup"

<br/>

Name              | \#define                   | Description
------------------|----------------------------|----------------------------------------------------------------
Memory Management | \c OS_EVR_MEMORY_LEVEL     | Recording level for Memory Management events.
Kernel            | \c OS_EVR_KERNEL_LEVEL     | Recording level for Kernel events.
Thread            | \c OS_EVR_THREAD_LEVEL     | Recording level for Thread events.
Generic Wait      | \c OS_EVR_WAIT_LEVEL       | Recording level for Generic Wait events.
Thread Flags      | \c OS_EVR_THFLAGS_LEVEL    | Recording level for Thread Flags events.
Event Flags       | \c OS_EVR_EVFLAGS_LEVEL    | Recording level for Event Flags events.
Timer             | \c OS_EVR_TIMER_LEVEL      | Recording level for Timer events.
Mutex             | \c OS_EVR_MUTEX_LEVEL      | Recording level for Mutex events.
Semaphore         | \c OS_EVR_SEMAPHORE_LEVEL  | Recording level for Semaphore events.
Memory Pool       | \c OS_EVR_MEMPOOL_LEVEL    | Recording level for Memory Pool events.
Message Queue     | \c OS_EVR_MSGQUEUE_LEVEL   | Recording level for Message Queue events.
 

\subsection evtrecConfigEvtGen RTOS Event Generation

Enable the event generation for specific RTX component groups. This requires the RTX source variant (refer to \ref cre_rtx_proj_er for more information).

\image html config_wizard_evtrecGeneration.png "RTX_Config.h: Event generation configuration"

<br/>

Name              | \#define                 | Description
------------------|--------------------------|----------------------------------------------------------------
Memory Management | \c OS_EVR_MEMORY         | Enables Memory Management events generation.
Kernel            | \c OS_EVR_KERNEL         | Enables Kernel events generation.
Thread            | \c OS_EVR_THREAD         | Enables Thread events generation.
Generic Wait      | \c OS_EVR_WAIT           | Enables Generic Wait events generation.
Thread Flags      | \c OS_EVR_THFLAGS        | Enables Thread Flags events generation.
Event Flags       | \c OS_EVR_EVFLAGS        | Enables Event Flags events generation.
Timer             | \c OS_EVR_TIMER          | Enables Timer events generation.
Mutex             | \c OS_EVR_MUTEX          | Enables Mutex events generation.
Semaphore         | \c OS_EVR_SEMAPHORE      | Enables Semaphore events generation.
Memory Pool       | \c OS_EVR_MEMPOOL        | Enables Memory Pool events generation.
Message Queue     | \c OS_EVR_MSGQUEUE       | Enables Message Queue events generation.

\note
If event generation for a component is disabled, the code that generates the related events is not included. Thus, \ref evtrecConfigGlobIni "filters" for this
component will have no effect and the debugger is unable to display any events for the related component group.


\subsection systemConfig_event_recording Manual event configuration

To disable the generation of events for a specific RTX API call, use the following \#define settings (from <b>rtx_evrt.h</b>) and add these manually 
to the <b>RTX_Config.h</b> file:

\b Memory \b events \n
\c EVR_RTX_MEMORY_INIT_DISABLE, \c EVR_RTX_MEMORY_ALLOC_DISABLE, \c EVR_RTX_MEMORY_FREE_DISABLE,
\c EVR_RTX_MEMORY_BLOCK_INIT_DISABLE, \c EVR_RTX_MEMORY_BLOCK_ALLOC_DISABLE, \c EVR_RTX_MEMORY_BLOCK_FREE_DISABLE

\b Kernel \b events \n
\c EVR_RTX_KERNEL_ERROR_DISABLE, \c EVR_RTX_KERNEL_INITIALIZE_DISABLE, \c EVR_RTX_KERNEL_INITIALIZED_DISABLE,
\c EVR_RTX_KERNEL_GET_INFO_DISABLE, \c EVR_RTX_KERNEL_INFO_RETRIEVED_DISABLE, \c EVR_RTX_KERNEL_GET_STATE_DISABLE,
\c EVR_RTX_KERNEL_START_DISABLE, \c EVR_RTX_KERNEL_STARTED_DISABLE, \c EVR_RTX_KERNEL_LOCK_DISABLE,
\c EVR_RTX_KERNEL_LOCKED_DISABLE, \c EVR_RTX_KERNEL_UNLOCK_DISABLE, \c EVR_RTX_KERNEL_UNLOCKED_DISABLE,
\c EVR_RTX_KERNEL_RESTORE_LOCK_DISABLE, \c EVR_RTX_KERNEL_LOCK_RESTORED_DISABLE, \c EVR_RTX_KERNEL_SUSPEND_DISABLE,
\c EVR_RTX_KERNEL_SUSPENDED_DISABLE, \c EVR_RTX_KERNEL_RESUME_DISABLE, \c EVR_RTX_KERNEL_RESUMED_DISABLE,
\c EVR_RTX_KERNEL_GET_TICK_COUNT_DISABLE, \c EVR_RTX_KERNEL_GET_TICK_FREQ_DISABLE,
\c EVR_RTX_KERNEL_GET_SYS_TIMER_COUNT_DISABLE, \c EVR_RTX_KERNEL_GET_SYS_TIMER_FREQ_DISABLE

\b Thread \b events \n
\c EVR_RTX_THREAD_ERROR_DISABLE, \c EVR_RTX_THREAD_NEW_DISABLE, \c EVR_RTX_THREAD_CREATED_DISABLE,
\c EVR_RTX_THREAD_GET_NAME_DISABLE, \c EVR_RTX_THREAD_GET_ID_DISABLE, \c EVR_RTX_THREAD_GET_STATE_DISABLE,
\c EVR_RTX_THREAD_GET_STACK_SIZE_DISABLE, \c EVR_RTX_THREAD_GET_STACK_SPACE_DISABLE, \c EVR_RTX_THREAD_SET_PRIORITY_DISABLE,
\c EVR_RTX_THREAD_PRIORITY_UPDATED_DISABLE, \c EVR_RTX_THREAD_GET_PRIORITY_DISABLE, \c EVR_RTX_THREAD_YIELD_DISABLE,
\c EVR_RTX_THREAD_SUSPEND_DISABLE, \c EVR_RTX_THREAD_SUSPENDED_DISABLE, \c EVR_RTX_THREAD_RESUME_DISABLE,
\c EVR_RTX_THREAD_RESUMED_DISABLE, \c EVR_RTX_THREAD_DETACH_DISABLE, \c EVR_RTX_THREAD_DETACHED_DISABLE,
\c EVR_RTX_THREAD_JOIN_DISABLE, \c EVR_RTX_THREAD_JOIN_PENDING_DISABLE, \c EVR_RTX_THREAD_JOINED_DISABLE,
\c EVR_RTX_THREAD_BLOCKED_DISABLE, \c EVR_RTX_THREAD_UNBLOCKED_DISABLE, \c EVR_RTX_THREAD_PREEMPTED_DISABLE,
\c EVR_RTX_THREAD_SWITCHED_DISABLE, \c EVR_RTX_THREAD_EXIT_DISABLE, \c EVR_RTX_THREAD_TERMINATE_DISABLE,
\c EVR_RTX_THREAD_DESTROYED_DISABLE, \c EVR_RTX_THREAD_GET_COUNT_DISABLE, \c EVR_RTX_THREAD_ENUMERATE_DISABLE

\b Generic \b wait \b events \n
\c EVR_RTX_DELAY_ERROR_DISABLE, \c EVR_RTX_DELAY_DISABLE, \c EVR_RTX_DELAY_UNTIL_DISABLE,
\c EVR_RTX_DELAY_STARTED_DISABLE, \c EVR_RTX_DELAY_UNTIL_STARTED_DISABLE, \c EVR_RTX_DELAY_COMPLETED_DISABLE 

\b Thread \b flag \b events \n
\c EVR_RTX_THREAD_FLAGS_ERROR_DISABLE, \c EVR_RTX_THREAD_FLAGS_SET_DISABLE, \c EVR_RTX_THREAD_FLAGS_SET_DONE_DISABLE,
\c EVR_RTX_THREAD_FLAGS_CLEAR_DISABLE, \c EVR_RTX_THREAD_FLAGS_CLEAR_DONE_DISABLE, \c EVR_RTX_THREAD_FLAGS_GET_DISABLE,
\c EVR_RTX_THREAD_FLAGS_WAIT_DISABLE, \c EVR_RTX_THREAD_FLAGS_WAIT_PENDING_DISABLE, \c EVR_RTX_THREAD_FLAGS_WAIT_TIMEOUT_DISABLE,
\c EVR_RTX_THREAD_FLAGS_WAIT_COMPLETED_DISABLE, \c EVR_RTX_THREAD_FLAGS_WAIT_NOT_COMPLETED_DISABLE

\b Event \b flag \b events \n
\c EVR_RTX_EVENT_FLAGS_ERROR_DISABLE, \c EVR_RTX_EVENT_FLAGS_NEW_DISABLE, \c EVR_RTX_EVENT_FLAGS_CREATED_DISABLE,
\c EVR_RTX_EVENT_FLAGS_GET_NAME_DISABLE, \c EVR_RTX_EVENT_FLAGS_SET_DISABLE, \c EVR_RTX_EVENT_FLAGS_SET_DONE_DISABLE,
\c EVR_RTX_EVENT_FLAGS_CLEAR_DISABLE, \c EVR_RTX_EVENT_FLAGS_CLEAR_DONE_DISABLE, \c EVR_RTX_EVENT_FLAGS_GET_DISABLE,
\c EVR_RTX_EVENT_FLAGS_WAIT_DISABLE, \c EVR_RTX_EVENT_FLAGS_WAIT_PENDING_DISABLE,
\c EVR_RTX_EVENT_FLAGS_WAIT_TIMEOUT_DISABLE, \c EVR_RTX_EVENT_FLAGS_WAIT_COMPLETED_DISABLE,
\c EVR_RTX_EVENT_FLAGS_WAIT_NOT_COMPLETED_DISABLE, \c EVR_RTX_EVENT_FLAGS_DELETE_DISABLE,
\c EVR_RTX_EVENT_FLAGS_DESTROYED_DISABLE

\b Timer \b events \n
\c EVR_RTX_TIMER_ERROR_DISABLE, \c EVR_RTX_TIMER_CALLBACK_DISABLE, \c EVR_RTX_TIMER_NEW_DISABLE,
\c EVR_RTX_TIMER_CREATED_DISABLE, \c EVR_RTX_TIMER_GET_NAME_DISABLE, \c EVR_RTX_TIMER_START_DISABLE,
\c EVR_RTX_TIMER_STARTED_DISABLE, \c EVR_RTX_TIMER_STOP_DISABLE, \c EVR_RTX_TIMER_STOPPED_DISABLE,
\c EVR_RTX_TIMER_IS_RUNNING_DISABLE, \c EVR_RTX_TIMER_DELETE_DISABLE, \c EVR_RTX_TIMER_DESTROYED_DISABLE

\b Mutex \b events \n
\c EVR_RTX_MUTEX_ERROR_DISABLE, \c EVR_RTX_MUTEX_NEW_DISABLE, \c EVR_RTX_MUTEX_CREATED_DISABLE,
\c EVR_RTX_MUTEX_GET_NAME_DISABLE, \c EVR_RTX_MUTEX_ACQUIRE_DISABLE, \c EVR_RTX_MUTEX_ACQUIRE_PENDING_DISABLE,
\c EVR_RTX_MUTEX_ACQUIRE_TIMEOUT_DISABLE, \c EVR_RTX_MUTEX_ACQUIRED_DISABLE, \c EVR_RTX_MUTEX_NOT_ACQUIRED_DISABLE,
\c EVR_RTX_MUTEX_RELEASE_DISABLE, \c EVR_RTX_MUTEX_RELEASED_DISABLE, \c EVR_RTX_MUTEX_GET_OWNER_DISABLE,
\c EVR_RTX_MUTEX_DELETE_DISABLE, \c EVR_RTX_MUTEX_DESTROYED_DISABLE

\b Semaphore \b events \n
\c EVR_RTX_SEMAPHORE_ERROR_DISABLE, \c EVR_RTX_SEMAPHORE_NEW_DISABLE, \c EVR_RTX_SEMAPHORE_CREATED_DISABLE,
\c EVR_RTX_SEMAPHORE_GET_NAME_DISABLE, \c EVR_RTX_SEMAPHORE_ACQUIRE_DISABLE, \c EVR_RTX_SEMAPHORE_ACQUIRE_PENDING_DISABLE,
\c EVR_RTX_SEMAPHORE_ACQUIRE_TIMEOUT_DISABLE, \c EVR_RTX_SEMAPHORE_ACQUIRED_DISABLE,
\c EVR_RTX_SEMAPHORE_NOT_ACQUIRED_DISABLE, \c EVR_RTX_SEMAPHORE_RELEASE_DISABLE, \c EVR_RTX_SEMAPHORE_RELEASED_DISABLE,
\c EVR_RTX_SEMAPHORE_GET_COUNT_DISABLE, \c EVR_RTX_SEMAPHORE_DELETE_DISABLE, \c EVR_RTX_SEMAPHORE_DESTROYED_DISABLE

\b Memory \b pool \b events \n
\c EVR_RTX_MEMORY_POOL_ERROR_DISABLE, \c EVR_RTX_MEMORY_POOL_NEW_DISABLE, \c EVR_RTX_MEMORY_POOL_CREATED_DISABLE,
\c EVR_RTX_MEMORY_POOL_GET_NAME_DISABLE, \c EVR_RTX_MEMORY_POOL_ALLOC_DISABLE, \c EVR_RTX_MEMORY_POOL_ALLOC_PENDING_DISABLE,
\c EVR_RTX_MEMORY_POOL_ALLOC_TIMEOUT_DISABLE, \c EVR_RTX_MEMORY_POOL_ALLOCATED_DISABLE,
\c EVR_RTX_MEMORY_POOL_ALLOC_FAILED_DISABLE, \c EVR_RTX_MEMORY_POOL_FREE_DISABLE, \c EVR_RTX_MEMORY_POOL_DEALLOCATED_DISABLE,
\c EVR_RTX_MEMORY_POOL_FREE_FAILED_DISABLE, \c EVR_RTX_MEMORY_POOL_GET_CAPACITY_DISABLE,
\c EVR_RTX_MEMORY_POOL_GET_BLOCK_SZIE_DISABLE, \c EVR_RTX_MEMORY_POOL_GET_COUNT_DISABLE,
\c EVR_RTX_MEMORY_POOL_GET_SPACE_DISABLE, \c EVR_RTX_MEMORY_POOL_DELETE_DISABLE, \c EVR_RTX_MEMORY_POOL_DESTROYED_DISABLE

\b Message \b queue \b events \n
\c EVR_RTX_MESSAGE_QUEUE_ERROR_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_NEW_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_CREATED_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_GET_NAME_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_PUT_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_PUT_PENDING_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_PUT_TIMEOUT_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_INSERT_PENDING_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_INSERTED_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_NOT_INSERTED_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_GET_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_GET_PENDING_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_GET_TIMEOUT_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_RETRIEVED_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_NOT_RETRIEVED_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_GET_CAPACITY_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_GET_MSG_SIZE_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_GET_COUNT_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_GET_SPACE_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_RESET_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_RESET_DONE_DISABLE,
\c EVR_RTX_MESSAGE_QUEUE_DELETE_DISABLE, \c EVR_RTX_MESSAGE_QUEUE_DESTROYED_DISABLE


*/


/* ========================================================================================================================== */
/** 
\page creating_RTX5_LIB Building the RTX5 Library

The CMSIS Pack contains a µVision project for building the complete set of RTX5 libraries. This project can also be used as
a reference for building the RTX5 libraries using a tool-chain of your choice.

-# Open the project \b RTX_CM.uvprojx from the pack folder <b>CMSIS/RTOS2/RTX/Library/ARM/MDK</b> in µVision.
-# Select the project target that matches your device's processor core. 
   \n The project provides target configuration for all supported Cortex-M targets supported by RTX5.
-# You can find out about the required preprocessor defines in the dialogs <b>Options for Target - C/C++</b> and
   <b>Options for Target - Asm</b>. Note the need to use at least the C99 compiler mode when building RTX from source.
-# From the <b>Project</b> window you find the list of source files required for a complete library build.
-# Build the library of your choice using \b Project - \b Build \b Target (or press F7).

\image html own_lib_projwin.png "Project with files for Armv8-M Mainline"
*/



/* ========================================================================================================================== */
/** 
\page technicalData5 Technical Data

The following section contains technical information about RTX v5.

 - \subpage pHardwareRequirements lists the resource requirements of the RTX v5 kernel along with hardware dependencies.
 - \subpage pStackRequirements lists the memory requirements for the main stack when running the RTX v5 kernel. 
 - \subpage pControlBlockSizes provides memory size information for \ref StaticObjectMemory "object-specific control block memory allocation".
 - \subpage pDirectory_Files is an overview of the supplied files that belong to RTX v5
\ifnot FuSaRTS
 - \subpage pToolchains details about the compiler support which includes ArmCC (MDK, DS-5), IAR EW-ARM, and GCC.
\endif


\page pHardwareRequirements Hardware Requirements

The following section lists the hardware requirements for RTX v5 on the various supported target processors:

\section tpProcessor Processor Requirements

RTX assumes a fully functionable processor and uses the following hardware features. It does not implement any confidence test for processor validation which should be provided by an user-supplied software test library.


\if ARMv8M \subsection tpCortexM0_M0P_M23 Cortex-M0/M0+/M23 target processor
\endif

\ifnot ARMv8M \subsection tpCortexM0_M0P_M23 Cortex-M0/M0+ target processor
\endif

Hardware Requirement       | Description
:--------------------------|:------------------------------------------------------
SysTick timer              | The SysTick timer generates the kernel tick interrupts and the interface is implemented in %os_systick.c using the \ref CMSIS_RTOS_TickAPI
Exception Handler          | RTX implements exception handlers for SVC, PendSV, and SysTick interrupt
Core Registers             | The processor status is read using the following core registers: CONTROL, IPSR, PRIMASK
System Control Block (SBC) | To control and setup the processor exceptions including PendSV and SVC
Interrupt Control          | The CMSIS-Core functions __disable_irq and __enable_irq to control the interrupt system via the CPSR core register.

The RTX implements interfaces to the processor hardware in following files: 
 - <b>%irq_cm0.s</b> defines exception handlers for Cortex-M0/M0+
\if ARMv8M
 - <b>%irq_armv8mbl_common.s</b> defines exception handlers for Cortex-M23
\endif 
 - <b>%rtx_core_cm.h</b> defines processor specific helper functions and the interfaces to Core Registers and Core Peripherals.
 - <b>%os_tick.h</b> is the \ref CMSIS_RTOS_TickAPI that defines the interface functions to the SysTick timer.

\note
 - The CMSIS-Core variable \c SystemCoreClock is used by RTX to configure the SysTick timer. 

\if ARMv8M \subsection tpCortexM3_M4_M7_M33_M35P Cortex-M3/M4/M7/M33/M35P target processor
\endif 

\ifnot ARMv8M \subsection tpCortexM3_M4_M7_M33_M35P Cortex-M3/M4/M7 target processor
\endif 

RTX assumes a fully function-able processor and uses the following hardware features:

Hardware Item       | Requirement Description
:--------------------------|:------------------------------------------------------
SysTick timer              | The \b SysTick timer shall be available in the processor. 
System Exceptions          | The RTX requires \b SVC, \b PendSV, and \b SysTick exceptions and implements corresponding exception handlers.
Core Registers             | The RTX uses \b CONTROL, \b IPSR , \b PRIMASK and \b BASEPRI core registers for reading processor status. 
System Control Block (SCB) | The RTX uses \b SCB registers to control and setup the processor system exceptions including PendSV and SVC.
NVIC Interface             | CMSIS-Core function \b NVIC_GetPriorityGrouping is used by the RTX to setup interrupt priorities.
LDREX, STREX instructions  | Exclusive access instructions \b LDREX and \b STREX are used to implement atomic execution without disabling interrupts.

The interface files to the processor hardware are: 
 - <b>%irq_cm3.s</b> defines exception handlers for Cortex-M3 and Cortex-M4/M7 without floating point unit.
 - <b>%irq_cm4f.s</b> defines exception handlers for Cortex-M4/M7 with floating point unit.
\if ARMv8M 
 - <b>%irq_armv8mml_common.s</b> defines exception handlers for Cortex-M33/M35P
\endif
 - <b>%rtx_core_cm.h</b> defines processor specific helper functions and the interfaces to Core Registers and Core Peripherals.
 - <b>%os_tick.h</b> is the \ref CMSIS_RTOS_TickAPI that defines the interface functions to the SysTick timer.

\note
 - The CMSIS-Core variable \c SystemCoreClock is used by RTX to configure the SysTick timer.

\if ARMCA \subsection tpCortexA5_A7_A9 Cortex-A5/A7/A9 target processor


Hardware Requirement       | Description
:--------------------------|:------------------------------------------------------
Timer Peripheral           | An arbitrary timer peripheral generates the kernel tick interrupts. The interfaces for Cortex-A Generic Timer and Private Timer are implemented in %os_tick_gtim.c and %os_tick_ptim.c using the \ref CMSIS_RTOS_TickAPI
Exception Handler          | RTX implements exception handlers for SVC, IRQ, Data Abort, Prefetch Abort and Undefined Instruction interrupt.
Core Registers             | The processor status is read using the following core registers: CPSR, CPACR and FPSCR.
LDREX, STREX instruction   | Atomic execution avoids the requirement to disable interrupts and is implemented via exclusive access instructions.
Interrupt Controller       | An interrupt controller interface is required to setup and control Timer Peripheral interrupt. The interface for Arm GIC (Generic Interrupt Controller) is implemented in %irq_ctrl_gic.c using the <a class="el" href="../../Core_A/html/group__irq__ctrl__gr.html">IRQ Controller API</a>.

The interface files to the processor hardware are: 
 - <b>%irq_ca.s</b> defines SVC, IRQ, Data Abort, Prefetch Abort and Undefined Instruction exception handlers.
 - <b>%rtx_core_ca.h</b> defines processor specific helper functions and the interfaces to Core Registers and Core Peripherals.
 - <b>%os_tick.h</b> is the \ref CMSIS_RTOS_TickAPI that defines the interface functions to the timer peripheral.
 - <b>%irq_ctrl.h</b> is the <a class="el" href="../../Core_A/html/group__irq__ctrl__gr.html">IRQ Controller API</a> that defines the interface functions to the interrupt controller.

\note
 - The CMSIS-Core variable \c SystemCoreClock is used by RTX to configure the timer peripheral.
\endif

\section rMemory Memory Requirements
RTX requires RAM memory that is accessible with contiguous linear addressing.  When memory is split across multiple memory banks, some systems 
do not accept multiple load or store operations on this memory blocks. 

RTX does not implement any confidence test for memory validation. This should be implemented by an user-supplied software test library.


\page pStackRequirements Stack Requirements

Keil RTX v5 kernel functions are executed in handler mode (using PendSV/SysTick/SVC) and the tables below lists the maximum stack requirements for the Main Stack (MSP) that the user
should consider. 

The stack for the \ref osKernelStart function is referred as "Startup" and RTX v5 uses 32 bytes (with Arm Compiler). However the user should also consider additional stack that
might be allocated by the 'main' function of the embedded application. The following picture shows a worst-case memory allocation of the Main Stack.

\image html "KernelStackUsage.png" "Main Stack usage of RTX v5 applications"

The stack requirements depend on the compiler and the optimization level.  RTX v5 supports event annotations and this configuration impacts also the stack requirement.

<b>Arm Compiler ARMCC V6.10</b>: Main Stack requirements for PendSV/SysTick/SVC

Optimization         | RTX Kernel  | RTX Kernel + Event Recorder
:--------------------|:------------|:--------------------------------
-O1 (Debug)          | 152 bytes   | 280 bytes   
-Os (Balanced)       | 120 bytes   | 256 bytes
-Oz (Size)           | 112 bytes   | 248 bytes

<b>Arm Compiler ARMCC V5.06</b>: Main Stack requirements for PendSV/SysTick/SVC

Optimization         | RTX Kernel  | RTX Kernel + Event Recorder
:--------------------|:------------|:--------------------------------
-O0 (Debug)          | 176 bytes   | 360 bytes   
-O1                  | 112 bytes   | 248 bytes
-O2                  | 112 bytes   | 256 bytes
-O3                  | 112 bytes   | 248 bytes


\page pControlBlockSizes Control Block Sizes

Keil RTX v5 specific control block definitions (including sizes) as well as memory pool and message queue memory requirements
are defined in the header file <b>rtx_os.h</b>:

If you provide memory for the RTOS objects, you need to know the size that is required for each object control block.
The memory of the control block is provided by the parameter \em attr of the related \em osXxxxNew function.
The element \em cb_mem is the memory address, \em cb_size is the size of the control block memory.

Refer to \ref StaticObjectMemory for more information.

The following table lists the control block sizes:

Category                      | Control Block Size Attribute      | Size       | \#define symbol
:-----------------------------|:----------------------------------|:-----------|:--------------------
\ref CMSIS_RTOS_ThreadMgmt    | \ref osThreadAttr_t::cb_mem       | 68 bytes   | \ref osRtxThreadCbSize
\ref CMSIS_RTOS_TimerMgmt     | \ref osTimerAttr_t::cb_mem        | 32 bytes   | \ref osRtxTimerCbSize
\ref CMSIS_RTOS_EventFlags    | \ref osEventFlagsAttr_t::cb_mem   | 16 bytes   | \ref osRtxEventFlagsCbSize
\ref CMSIS_RTOS_MutexMgmt     | \ref osMutexAttr_t::cb_mem        | 28 bytes   | \ref osRtxMutexCbSize
\ref CMSIS_RTOS_SemaphoreMgmt | \ref osSemaphoreAttr_t::cb_mem    | 16 bytes   | \ref osRtxSemaphoreCbSize
\ref CMSIS_RTOS_PoolMgmt      | \ref osMemoryPoolAttr_t::cb_mem   | 36 bytes   | \ref osRtxMemoryPoolCbSize
\ref CMSIS_RTOS_Message       | \ref osMessageQueueAttr_t::cb_mem | 52 bytes   | \ref osRtxMessageQueueCbSize


\page pDirectory_Files Directory Structure and File Overview

The following section provides an overview of the directory structure and the files that are relevant for the user's for
CMSIS-RTOS RTX v5. The following directory references start below the CMSIS pack installation path, for example
ARM/CMSIS/<i>version</i>/CMSIS/RTOS2.

\section Folders RTX v5 Directory Structure

The CMSIS-RTOS RTX v5 is delivered in source code and several examples are provided. 

<table class="cmtable" summary="CMSIS-RTOS RTX Library Files">
    <tr>
      <th>Directory</th>
      <th>Content</th>
    </tr>
    <tr>
      <td>Include</td>
      <td>Header files: \b %cmsis_os2.h for \ref rtos_api2 and \b %os_tick.h for \ref rtos_os_tick_api.</td>
    </tr>
    <tr>
      <td>Source</td>
      <td>Generic <b>OS tick</b> implementations for various processors based on \ref rtos_os_tick_api.</td>
    </tr>
    <tr>
      <td>Template</td>
      <td><a class="el" href="../../RTOS/html/index.html">CMSIS-RTOS API v1</a> template source and header file.</td>
    </tr>
    <tr>
      <td>RTX</td>
      <td>Directory with RTX specific files and folders. Also contains the component viewer description file.</td>
    </tr>
    <tr>
      <td>RTX/Config</td>
      <td>CMSIS-RTOS RTX configuration files %RTX_Config.h and %RTX_Config.c.</td>
    </tr>
    <tr>
      <td>RTX/Examples</td>
      <td>Example projects that can be directly used in development tools.</td>
    </tr>
    <tr>
      <td>RTX/Include</td>
      <td>RTX v5 specific include files.</td>
    </tr>
    <tr>
      <td>RTX/Include1</td>
      <td>CMSIS-RTOS v1 API header file.</td>
    </tr>
    <tr>
      <td>RTX/Library</td>
      <td>Pre-built libraries (see next table for details).</td>
    </tr>
    <tr>
      <td>RTX/Source</td>
      <td>Source code that can be used with ARMCC and GCC.</td>
    </tr>
    <tr>
      <td>RTX/Template</td>
      <td>User code templates for creating application projects with CMSIS-RTOS RTX v5.</td>
    </tr>
</table>

\section libFiles RTX v5 Library Files

The CMSIS-RTOS RTX Library is available pre-compiled for ARMCC and GCC compilers and supports all Cortex-M
processor variants in every configuration  \if ARMv8M , including Arm Cortex-M23, Cortex-M33 and Cortex-M35P\endif.

<table class="cmtable" summary="CMSIS-RTOS RTX Library Files">
    <tr>
      <th>Library File</th>
      <th>Processor Configuration</th>
    </tr>
    <tr>
      <td>Library/ARM/RTX_CM0.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Cortex-M0 and M1, little-endian.</td>
    </tr>
    <tr>
      <td>Library/ARM/RTX_CM3.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Cortex-M3, M4, and M7 without FPU, little-endian.</td>
    </tr>
    <tr>
      <td>Library/ARM/RTX_CM4F.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Cortex-M4 and M7 with FPU, little-endian.</td>
    </tr>
\if ARMv8M      
    <tr>
      <td>Library/ARM/RTX_V8MB.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Armv8-M Baseline.</td>
    </tr>
    <tr>
      <td>Library/ARM/RTX_V8MBN.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Armv8-M Baseline, non-secure.</td>
    </tr>
    <tr>
      <td>Library/ARM/RTX_V8MM.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Armv8-M Mainline.</td>
    </tr>
    <tr>
      <td>Library/ARM/RTX_V8MMF.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Armv8-M Mainline with FPU.</td>
    </tr>
    <tr>
      <td>Library/ARM/RTX_V8MMFN.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Armv8-M Mainline with FPU, non-secure.</td>
    </tr>
    <tr>
      <td>Library/ARM/RTX_V8MMN.lib</td>
      <td>CMSIS-RTOS RTX Library for ARMCC Compiler, Armv8-M Mainline, non-secure.</td>
    </tr>
\endif  
\ifnot FuSaRTS
    <tr>
      <td>Library/GCC/libRTX_CM0.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Cortex-M0 and M1, little-endian.</td>
    </tr>
    <tr>
      <td>Library/GCC/libRTX_CM3.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Cortex-M3, M4, and M7 without FPU, little-endian.</td>
    </tr>
    <tr>
      <td>Library/GCC/libRTX_CM4F.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Cortex-M4 and M7 with FPU, little-endian.</td>
    </tr>
\endif  
\if ARMv8M      
    <tr>
      <td>Library/GCC/libRTX_V8MB.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Armv8-M Baseline.</td>
    </tr>
    <tr>
      <td>Library/GCC/libRTX_V8MBN.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Armv8-M Baseline, non-secure.</td>
    </tr>
    <tr>
      <td>Library/GCC/libRTX_V8MM.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Armv8-M Mainline.</td>
    </tr>
    <tr>
      <td>Library/GCC/libRTX_V8MMF.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Armv8-M Mainline with FPU.</td>
    </tr>
    <tr>
      <td>Library/GCC/libRTX_V8MMFN.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Armv8-M Mainline with FPU, non-secure.</td>
    </tr>
    <tr>
      <td>Library/GCC/libRTX_V8MMN.a</td>
      <td>CMSIS-RTOS libRTX Library for GCC Compiler, Armv8-M Mainline, non-secure.</td>
    </tr>
\endif
</table>
*/



/**
\ifnot FuSaRTS \page pToolchains Supported Toolchains

Keil RTX5 is developed and tested using the common toolchains and development environments.

\section technicalData_Toolchain_ARM Arm Compiler (Arm/Keil MDK, uVision5)

RTX5 is initially developed and optimized using Arm Compiler and Arm/Keil MDK.
The current release is tested with the following versions:
<ul>
 <li>Arm Compiler 5.06 Update 6</li>
 <li>Arm Compiler 6.6.2 (Long Term Maintenance)</li>
 <li>Arm Compiler 6.9</li>
 <li>RTOS-aware debugging with uVision 5.24</li>
</ul>


\section technicalData_Toolchain_IAR IAR Embedded Workbench

RTX5 has been ported to the IAR Embedded Workbench. The following releases are known to work:
<ul>
 <li>IAR Embedded Workbench 7.7 (<a href="https://github.com/ARM-software/CMSIS_5/issues/201">community report</a>)</li>
 <li>IAR Embedded Workbench 7.80.4</li>
 <li><b>IAR Embedded Workbench 8.20.1</b></li>
</ul>

\section technicalData_Toolchain_GCC GNU Compiler Collection

RTX5 has also been ported to support GCC, maintenance mainly relays on community contribution.
Active development is currently tested with:
<ul>
 <li>GNU Tools for Arm Embedded 6.3.1 20170620</li>
</ul>

\endif
*/


/* ========================================================================================================================== */
/** 
\page CodingRules Coding Rules

CMSIS components use <a href="../../General/html/index.html#CodingRules"><b>general coding rules</b></a> across the various components.

The CMSIS-RTOS2 API is using the following <b>Namespace</b> prefixes:
  - <b>os</b> for all definitions and function names.
  - <b>os</b> with postfix <b>_t</b> for all typedefs.
  
The CMSIS-RTOS2 RTX v5 implementation is using the following <b>Namespace</b> prefixes for public symbol definitions:
  - <b>osRtx</b> for all general definitions and function names that relate to the RTX kernel.
  - <b>osRtx</b> with postfix <b>_t</b> for all typedefs.
  - <b>OS_Tick_</b> for interface functions to the hardware system tick timer.
  - <b>EvrRtx</b> for event function annotations that interface to the Event Recorder.
*/

/* ========================================================================================================================== */
/** 
\page misraCompliance5 MISRA C:2012 Compliance 
The RTX5 C source files use <b><a class=el href="http://www.misra.org.uk/" target="_blank">MISRA C:2012</a></b> guidelines as underlying coding standard.

For MISRA validation, <b><a class=el href="http://www.gimpel.com/" target="_blank">PC-lint</a></b> V9.00L is used with configuration for Arm Compiler V6.9.
The PC-Lint validation setup is part of the project file <b>.\\CMSIS\\RTOS2\\RTX\\Library\\ARM\\MDK\\RTX_CM.uvprojx</b> as shown below. 
Refer to <b><a class=el href="http://www.keil.com/support/man/docs/uv4/uv4_ut_pclint_validation.htm" target="_blank">Setup for PC-Lint</a></b> for more information.

\image html "PC-Lint.png" "Running PC-Lint within MDK - uVision"

The PC-Lint configuration uses the following Options under <b>Tools - PC-Lint Setup...</b>:
 - Config File: co-ARMCC-6.lnt (20-Mar-2017) with additional options:
\code
   +rw(__restrict)
   -esym(526,__builtin_*) -esym(628,__builtin_*)
   -sem(__builtin_clz, pure)
   +doffsetof(t,m)=((size_t)&((t*)0)->m) -emacro((413,923,9078),offsetof)
   -ecall(534,__disable_irq)
\endcode
 - Included Project Information: 
   - Enable: Add 'Include' paths
   - Enable: Add 'Software Packs' paths
   - Enable: Verify 'Software Packs' includes
   - Enable: Add 'Preprocessor' symbols
   - Enable: Add 'Define' symbols
 - MISRA  Rules Setup and Configuration: 
   - MISRQ_C_2012_Config.lnt; all rules enabled
   - includes definition file: au-misra3.lnt (12-Jun-2014)
 - Additional Lint Commands (for both single and mutiple files):
\code
   - emacro(835,osRtxConfigPrivilegedMode)
\endcode

The C source code is annotated with PC-Lint control comments to allows MISRA deviations.
These deviations with the underlaying design decisions are described in the following.
   
Deviations
----------

The RTX source code has the following deviations from MISRA:
  - \ref MISRA_1
  - \ref MISRA_2
  - \ref MISRA_3
  - \ref MISRA_4
  - \ref MISRA_5
  - \ref MISRA_6
  - \ref MISRA_7
  - \ref MISRA_8
  - \ref MISRA_9
  - \ref MISRA_10
  - \ref MISRA_11
  - \ref MISRA_12
  - \ref MISRA_13

All source code deviations are clearly marked and in summary these deviations affect the following MISRA rules:
 - [MISRA 2012 Directive  4.9,  advisory]: A function should be used in preference to a function-like macro where yet are interchangeable
 - [MISRA 2012 Rule       1.3,  required]: There shall be no occurrence of undefined or critical unspecified behavior
 - [MISRA 2012 Rule      10.3,  required]: Expression assigned to a narrower or different essential type
 - [MISRA 2012 Rule      10.5,  advisory]: Impermissible cast; cannot cast from 'essentially unsigned' to 'essentially enum\<i\>'
 - [MISRA 2012 Rule      11.1,  required]: Conversions shall not be performed between a pointer to a function and any other type
 - [MISRA 2012 Rule      11.3,  required]: A cast shall not be performed between a pointer to object type and a pointer to a different object type
 - [MISRA 2012 Rule      11.4,  advisory]: A conversion should not be performed between a pointer to object and an integer type
 - [MISRA 2012 Rule      11.5,  advisory]: A conversion should not be performed from pointer to void into pointer to object
 - [MISRA 2012 Rule      11.6,  required]: A cast shall not be performed between pointer to void and an arithmetic type
 - [MISRA 2012 Rule      15.5,  advisory]: A function should have a single point of exit at the end
 - [MISRA 2012 Rule      20.10, advisory]: The # and ## preprocessor operators should not be used

In the following all deviations are described in detail.

\section MISRA_1 [MISRA Note 1]: Return statements for parameter checking

Return statements are used at the beginning of several functions to validate parameter values and object states.
The function returns immediately without any side-effects and typically an error status is set. This structure
keeps the source code better structured and easier to understand.

This design decision implies the following MISRA deviation:
 - [MISRA 2012 Rule      15.5,  advisory]: A function should have a single point of exit at the end

All locations in the source code are marked with: 
\code
  //lint -e{904} "Return statement before end of function" [MISRA Note 1]
\endcode 


\section MISRA_2 [MISRA Note 2]: Object identifiers are void pointers

CMSIS-RTOS is independant of an underlying RTOS implementation. The object idenifiers are therefore defined as void pointers to:
  - allow application programs that are agnostic from an underlying RTOS implementation.
  - avoid accidently accesses an RTOS control block from an application program.

This design decisions imply the following MISRA deviations:
 - [MISRA 2012 Rule      11.3,  required]: A cast shall not be performed between a pointer to object type and a pointer to a different object type
 - [MISRA 2012 Rule      11.5,  advisory]: A conversion should not be performed from pointer to void into pointer to object

All locations in the source code are marked with: 
\code
  //lint -e{9079} -e{9087} "cast from pointer to void to pointer to object type" [MISRA Note 2]
\endcode 

In the RTX5 implementation the requried pointer conversions are implemented in the header file rtx_lib.h with the following inline functions:

\code
osRtxThread_t       *osRtxThreadId (osThread_t thread_id);
osRtxTimer_t        *osRtxTimerId (osTimer_t timer_id);
osRtxEventFlags_t   *osRtxEventFlagsId (osEventFlags_t ef_id);
osRtxMutex_t        *osRtxMutexId (osMutex_t mutex_id);
osRtxSemaphore_t    *osRtxSemaphoreId (osSemaphore_t semaphore_id);
osRtxMemoryPool_t   *osRtxMemoryPoolId (osMemoryPoolId_t mp_id);
osRtxMessageQueue_t *osRtxMessageQueueId(osMessageQueueId_t mq_id);
\endcode

\section MISRA_3 [MISRA Note 3]: Conversion to unified object control blocks

RTX uses a unified object control block structure that contains common object members.
The unified control blocks use a fixed layout at the beginning of the sturcture and starts always with an object identifier.
This allows common object functions that receive a pointer to a unified object control block and reference only the
pointer or the members in the fixed layout. Using common object functions and data (for example the ISR queue) reduces 
code complexity and keeps the source code better structured.  Refer also to \ref MISRA_4

This design decisions imply the following MISRA deviations:
 - [MISRA 2012 Rule      11.3,  required]: A cast shall not be performed between a pointer to object type and a pointer to a different object type
 - [MISRA 2012 Rule      11.5,  advisory]: A conversion should not be performed from pointer to void into pointer to object

All locations in the source code are marked with: 
\code
  //lint -e{9079} -e{9087} "cast from pointer to void to pointer to object type" [MISRA Note 3]
\endcode 


In the RTX5 implementation the requried pointer conversions are implemented in the header file \em rtx_lib.h with the following inline function:

\code
osRtxObject_t *osRtxObject (void *object);
\endcode


\section MISRA_4 [MISRA Note 4]: Conversion from unified object control blocks

RTX uses a unified object control block structure that contains common object members. Refer to \ref MISRA_3 for more information.
To process specifc control block data, pointer conversions are required.

This design decisions imply the following MISRA deviations:
 - [MISRA 2012 Rule       1.3,  required]: There shall be no occurrence of undefined or critical unspecified behavior
 - [MISRA 2012 Rule      11.3,  required]: A cast shall not be performed between a pointer to object type and a pointer to a different object type
In addition PC-Lint issues:
 - Info  826: Suspicious pointer-to-pointer conversion (area too small)

All locations in the source code are marked with: 
\code
  //lint -e{740} -e{826} -e{9087} "cast from pointer to generic object to specific object" [MISRA Note 4]
\endcode 

In the RTX5 source code the requried pointer conversions are implemented in the header file \em rtx_lib.h with the following inline functions:

\code
osRtxThread_t       *osRtxThreadObject (osRtxObject_t *object);
osRtxTimer_t        *osRtxTimerObject (osRtxObject_t *object);
osRtxEventFlags_t   *osRtxEventFlagsObject (osRtxObject_t *object);
osRtxMutex_t        *osRtxMutexObject (osRtxObject_t *object);
osRtxSemaphore_t    *osRtxSemaphoreObject (osRtxObject_t *object);
osRtxMemoryPool_t   *osRtxMemoryPoolObject (osRtxObject_t *object);
osRtxMessageQueue_t *osRtxMessageQueueObject (osRtxObject_t *object);
osRtxMessage_t      *osRtxMessageObject (osRtxObject_t *object);
\endcode

\section MISRA_5 [MISRA Note 5]: Conversion to object types

The RTX5 kernel has common memory management functions that use void pointers. These memory allocation fuctions returns 
a void pointer which is correctly aligned for object types.

This design decision implies the following MISRA deviations:
 - [MISRA 2012 Rule      11.5,  advisory]: A conversion should not be performed from pointer to void into pointer to object

All locations in the source code are marked with: 
\code
  //lint -e{9079} "conversion from pointer to void to pointer to other type" [MISRA Note 5]
\endcode 

Code example:

\code 
  os_thread_t  *thread;
   :
  //lint -e{9079} "conversion from pointer to void to pointer to other type" [MISRA Note 5]
  thread = osRtxMemoryPoolAlloc(osRtxInfo.mpi.thread);
\endcode



\section MISRA_6 [MISRA Note 6]: Conversion from user provided storage

CMSIS-RTOS2 and RTX5 support user provided storage for object control blocks, stack, and data storage.
The API uses void pointers to define the location of this user provided storage. It is therefore
required to cast the void pointer to underlying storage types. Alignment restrictions of user provided storage 
are checked before accessing memory. Refer also to \ref MISRA_7.

This design decisions imply the following MISRA deviations:
 - [MISRA 2012 Rule      11.3,  required]: A cast shall not be performed between a pointer to object type and a pointer to a different object type
 - [MISRA 2012 Rule      11.5,  advisory]: A conversion should not be performed from pointer to void into pointer to object

All locations in the source code are marked with: 
\code
  //lint -e{9079} "conversion from pointer to void to pointer to other type" [MISRA Note 6]
\endcode 

Code example:
\code
static osTimerId_t svcRtxTimerNew (osTimerFunc_t func, osTimerType_t type, void *argument, const osTimerAttr_t *attr) {
  os_timer_t *timer;
    :
  if (attr != NULL) {
    :
    //lint -e{9079} "conversion from pointer to void to pointer to other type" [MISRA Note 6]
    timer = attr->cb_mem;
        :
\endcode        

\section MISRA_7 [MISRA Note 7]: Check for proper pointer alignment

RTX5 verifies the alignment of user provided storage for object control blocks, stack, and data storage.
Refer also to \ref MISRA_6 for more information.

This design decision implies the following MISRA deviations:
 - [MISRA 2012 Rule      11.4,  advisory]: A conversion should not be performed between a pointer to object and an integer type
 - [MISRA 2012 Rule      11.6,  required]: A cast shall not be performed between pointer to void and an arithmetic type

All locations in the source code are marked with: 
\code
  //lint -e(923) -e(9078) "cast from pointer to unsigned int" [MISRA Note 7]
\endcode

Code example:
\code
static osThreadId_t svcRtxThreadNew (osThreadFunc_t func, void *argument, const osThreadAttr_t *attr) {
    :
  void         *stack_mem;
    :
  if (stack_mem != NULL) {
    //lint -e(923) -e(9078) "cast from pointer to unsigned int" [MISRA Note 7]
    if ((((uint32_t)stack_mem & 7U) != 0U) || (stack_size == 0U)) {
    :
\endcode        

\section MISRA_8 [MISRA Note 8]: Memory allocation management

RTX5 implements memory allocation functions which require pointer arithmetic to manage memory.
The structure with the type \em mem_block_t that is used to menage memory allocation blocks is defined in \em rtx_memory.c

This design decision implies the following MISRA deviations:
 - [MISRA 2012 Rule      11.4,  advisory]: A conversion should not be performed between a pointer to object and an integer type
 - [MISRA 2012 Rule      11.6,  required]: A cast shall not be performed between pointer to void and an arithmetic type

All locations in the source code are marked with: 
\code
  //lint -e(923) -e(9078) "cast from pointer to unsigned int" [MISRA Note 8]
\endcode

The required pointer arithmetic is implemented in \em rtx_memory.c with the following function:
\code
__STATIC_INLINE mem_block_t *MemBlockPtr (void *mem, uint32_t offset) {
  uint32_t     addr;
  mem_block_t *ptr;

  //lint --e{923} --e{9078} "cast between pointer and unsigned int" [MISRA Note 8]
  addr = (uint32_t)mem + offset;
  ptr  = (mem_block_t *)addr;

  return ptr;
}
\endcode

\section MISRA_9 [MISRA Note 9]: Pointer conversions for register access

The CMSIS-Core peripheral register blocks are accessed using a structure. The memory address of this structure 
is specified as unsigned integer number. Pointer conversions are required to access the specific registers.

This design decision implies the following MISRA deviations:
 - [MISRA 2012 Rule      11.4,  advisory]: A conversion should not be performed between a pointer to object and an integer type
 - [MISRA 2012 Rule      11.6,  required]: A cast shall not be performed between pointer to void and an arithmetic type

All locations in the source code are marked with: 
\code
  //lint -emacro((923,9078),SCB) "cast from unsigned long to pointer" [MISRA Note 9]
\endcode


Code example:
\code
#define SCS_BASE  (0xE000E000UL)
#define SCB      ((SCB_Type *)SCB_BASE)
typedef struct {...} SCB_Type;

SCB->... = ...;
\endcode

\section MISRA_10 [MISRA Note 10]: SVC calls use function-like macros

RTX5 is using SVC (Service Calls) to switch between thread mode (for user code execution) and handler mode (for RTOS kernel execution).
The SVC function call mechanism is implemented with assembly instructions to construct the code for SVC.
The source code uses C macros and are designed as C function-like macros to generate parameter passing
for variables depending on macro parameters. An alternative replacement code would be complex.
The C macros use multiple '##' operators however it has been verified that the order of evaluation is irrelevant 
and result of macro expansion is always predictable.

This design decision implies the following MISRA deviations:
 - [MISRA 2012 Directive  4.9,  advisory]: A function should be used in preference to a function-like macro where yet are interchangeable
 - [MISRA 2012 Rule       1.3,  required]: There shall be no occurrence of undefined or critical unspecified behavior
 - [MISRA 2012 Rule      20.10, advisory]: The # and ## preprocessor operators should not be used

The relevant source code is in the file \em rtx_core_cm.h and is marked with: 
\code
  //lint -save -e9023 -e9024 -e9026 "Function-like macros using '#/##'" [MISRA Note 10]
\endcode


\section MISRA_11 [MISRA Note 11]: SVC calls use assembly code

The SVC (Service Call) functions are constructed as a mix of C and inline assembly as it is required to access CPU registers
for parameter passing. The function parameters are mapped to the CPU registers R0..R3 and SVC function number to 
CPU register R12 (or R7). For assembly inter-working the function parameters are casted to unsigned int values.

The function return value after SVC call is mapped to the CPU register R0. Return value is casted from unsigned int 
to the target value. 

It has been verified that this method has has no side-effects and is well defined.

This design decision implies the following MISRA deviations:
 - [MISRA 2012 Rule      10.3,  required]: Expression assigned to a narrower or different essential type
 - [MISRA 2012 Rule      10.5,  advisory]: Impermissible cast; cannot cast from 'essentially unsigned' to 'essentially enum\<i\>'
 - [MISRA 2012 Rule      11.1,  required]: Conversions shall not be performed between a pointer to a function and any other type
 - [MISRA 2012 Rule      11.4,  advisory]: A conversion should not be performed between a pointer to object and an integer type
 - [MISRA 2012 Rule      11.6,  required]: A cast shall not be performed between pointer to void and an arithmetic type

SVC functions are marked as library modules and not processed by PC-lint. The relevant source code is marked with: 
\code
  //lint ++flb "Library Begin" [MISRA Note 11]
    :
  //lint --flb "Library End"
\endcode

Code example:
\code
//  Service Calls definitions
//lint ++flb "Library Begin" [MISRA Note 11]
SVC0_1(Delay,      osStatus_t, uint32_t)
SVC0_1(DelayUntil, osStatus_t, uint32_t)
//lint --flb "Library End"
\endcode

PC-lint does not process ASM input/output operand lists and therefore falsely identifies issues:
 - Last value assigned to variable not used
 - Symbol not subsequently referenced
\todo: what has been done to mitigate that?


\section MISRA_12 [MISRA Note 12]: Usage of exclusive access instructions

The RTX5 implementation uses the CPU instructions LDREX and STREX (when supported by the processor) to implement atomic operations.
This atomic operations elimite the requirement for interrupt lock-outs. The atomic operations are implemented using 
inline assembly.

PC-lint cannot process assembler instructions including the input/output operand lists and therefore falsely identifies issues:
 - Symbol not initialized
 - Symbol not subsequently referenced
 - Symbol not referenced
 - Pointer parameter could be declared as pointing to const

It has been verified that atomic operations have no side-effects and are well defined.

The functions that implement atomic instructions are marked as library modules and not processed by PC-lint. The relevant source code is marked with: 
\code
  //lint ++flb "Library Begin" [MISRA Note 12]
    :
  //lint --flb "Library End"
\endcode


\section MISRA_13 [MISRA Note 13]: Usage of Event Recorder

The Event Recorder is a generic event logger and the related functions are called to record an event.
The function parameters are 32-bit id, 32-bit values, pointer to void (data) and are recorded as 32-bit numbers.
The parameters for the Event Recorder may require cast opertions to unsigned int which however has no side-effects 
and is well defined. 

The return value indicates success or failure. There is no need to check the return value since no action is 
taken when a Event Recorder function fail. The EventID macro (part of external Event Recorder) constructs the 
ID based on input parameters which are shifted, masked with '&' and combined with '|'.
Zero value input parameters are valid and cause zero used with '&' and '|'.

The usage of the Event Recorder implies the following MISRA deviations:
 - [MISRA 2012 Rule      11.1,  required]: Conversions shall not be performed between a pointer to a function and any other type
 - [MISRA 2012 Rule      11.4,  advisory]: A conversion should not be performed between a pointer to object and an integer type
 - [MISRA 2012 Rule      11.6,  required]: A cast shall not be performed between pointer to void and an arithmetic type
In addition PC-Lint issues:
 - Info  835: A zero has been given as left argument to operator '&'
 - Info  845: The right argument to operator '|' is certain to be 0

The functions that call the Event Recorder are in the module \em rtx_evr.c and the related PC-Lint messages are disabled with:
\code
  //lint -e923 -e9074 -e9078 -emacro((835,845),EventID) [MISRA Note 13]
\endcode

*/

/*=======0=========1=========2=========3=========4=========5=========6=========7=========8=========9=========0=========1====*/
/**
\page functionOverview Function Overview

CMSIS-RTOS2 provides multiple API interfaces:
  - \subpage rtos_api2 is the new C function interface that supports dynamic object creation \if ARMv8M and Armv8-M (Arm Cortex-M23,
    Cortex-M33 and Cortex-M35P) \endif.
  - <a class="el" href="../../RTOS/html/functionOverview.html">CMSIS-RTOS C API v1</a> is a C function API that is backward
    compatible with CMSIS-RTOS v1.
  - \subpage rtos_apicpp is a C++ class function API (future extension).

It is possible to intermix the different API variants in the same application and even in the same C/C++ source module.
However, the functions of the <a class="el" href="../../RTOS/html/functionOverview.html">CMSIS-RTOS C API v1</a> may be deprecated in future versions of CMSIS-RTOS.

CMSIS-RTOS2 defines also a generic system timer interface that works across the supported Arm Cortex processors:
  - \subpage rtos_os_tick_api is the interface to a kernel system timer.
*/

/*=======0=========1=========2=========3=========4=========5=========6=========7=========8=========9=========0=========1====*/
/**
\page rtos_api2 CMSIS-RTOS C API v2

Overview of all CMSIS-RTOS C API v2 functions that are implemented in the \subpage cmsis_os2_h. 

\section rtos_api2_basics Common Design Concepts

All RTOS objects share a common design concept. The overall life-cycle of
an object can be summarized as created -> in use -> destroyed.

<b>Create Objects</b>

An object is created by calling its `osXxxNew` function. The new function returns an identifier
that can be used to operate with the new object. The actual state of an object is typically stored
in an object specific control block. The memory layout (and size needed) for the control
block is implementation specific. One should not make any specific assumptions about the control
block. The control block layout might change and hence should be seen as an implementation
internal detail.

In order to expose control about object specific options all `osXxxNew` functions provide an
optional `attr` argument, which can be left as \token{NULL} by default. It takes a pointer to
an object specific attribute structure, commonly containing the fields
 - `name` to attach a human readable name to the object for identification,
 - `attr_bits` to control object-specific options,
 - `cb_mem` to provide memory for the control block manually, and
 - `cb_size` to quantify the memory size provided for the control block.

The `name` attribute is only used for object identification, e.g. using RTOS-aware debugging. The
attached string is not used for any other purposes internally.

The `cb_mem` and `cb_size` attributes can be used to provide memory for the control block manually
instead of relying on the implementation internal memory allocation. One has to assure that the
amount of memory pointed to by `cb_mem` is sufficient for the objects control block structure. If
the size given as `cb_size` is not sufficient the `osXxxNew` function returns with an error, i.e.
returning \token{NULL}. Furthermore providing control block memory manually is less portable. Thus
one has to take care about implementation specific alignment and placement requirements for instance.
Refer to \ref CMSIS_RTOS_MemoryMgmt for further details.

<b>Object Usage</b>

After an object has been created successfully it can be used until it is destroyed. The actions
defined for an object depends on its type. Commonly all the `osXxxDoSomething` access function
require the reference to the object to work with as the first `xxx_id` parameter.

The access function can be assumed to apply some sort of sanity checking on the id parameter. So
that it is assured one cannot accidentally call an access function with a \token{NULL} object
reference. Furthermore the concrete object type is verified, i.e. one cannot call access functions
of one object type with a reference to another object type.

All further parameter checks applied are either object and action specific or may even be implementation
specific. Thus one should always check action function return values for `osErrorParameter` to asure the
provided arguments were accepted.

As a rule of thumb only non-blocking access function can be used from \ref CMSIS_RTOS_ISR_Calls "Interrupt Service Routines" (ISR).
This incorporates `osXxxWait` functions (and similar) limited to be called with parameter `timeout`
set to \token{0}, i.e. usage of try-semantics.

<b>Object Destruction</b>

Objects that are not needed anymore can be destructed on demand to free the control block memory. Objects
are not destructed implicitly. Thus one can assume an object id to be valid until `osXxxDelete` is called
explicitly. The delete function finally frees the control block memory. In case of user provided control
block memory, see above, the memory must be freed manually as well. 

The only exception one has to take care of are Threads which do not have an explicit `osThreadDelete` function.
Threads can either be `detached` or `joinable`. Detached threads are automatically destroyed on termination,
i.e. call to \ref osThreadTerminate or \ref osThreadExit or return from thread function. On the other hand joinable
threads are kept alive until one explicitly calls \ref osThreadJoin.

\section rtos_api2_functions Function Reference

 - \ref CMSIS_RTOS_KernelCtrl
   - \ref osKernelGetInfo : \copybrief osKernelGetInfo
   - \ref osKernelGetState : \copybrief osKernelGetState
   - \ref osKernelGetSysTimerCount : \copybrief osKernelGetSysTimerCount
   - \ref osKernelGetSysTimerFreq : \copybrief osKernelGetSysTimerFreq
   - \ref osKernelInitialize : \copybrief osKernelInitialize
   - \ref osKernelLock : \copybrief osKernelLock
   - \ref osKernelUnlock : \copybrief osKernelUnlock
   - \ref osKernelRestoreLock : \copybrief osKernelRestoreLock
   - \ref osKernelResume : \copybrief osKernelResume
   - \ref osKernelStart : \copybrief osKernelStart
   - \ref osKernelSuspend : \copybrief osKernelSuspend
   - \ref osKernelGetTickCount : \copybrief osKernelGetTickCount
   - \ref osKernelGetTickFreq : \copybrief osKernelGetTickFreq

 - \ref CMSIS_RTOS_ThreadMgmt
   - \ref osThreadDetach : \copybrief osThreadDetach
   - \ref osThreadEnumerate : \copybrief osThreadEnumerate
   - \ref osThreadExit : \copybrief osThreadExit
   - \ref osThreadGetCount : \copybrief osThreadGetCount
   - \ref osThreadGetId : \copybrief osThreadGetId
   - \ref osThreadGetName : \copybrief osThreadGetName
   - \ref osThreadGetPriority : \copybrief osThreadGetPriority
   - \ref osThreadGetStackSize : \copybrief osThreadGetStackSize
   - \ref osThreadGetStackSpace : \copybrief osThreadGetStackSpace
   - \ref osThreadGetState : \copybrief osThreadGetState
   - \ref osThreadJoin : \copybrief osThreadJoin
   - \ref osThreadNew : \copybrief osThreadNew
   - \ref osThreadResume : \copybrief osThreadResume
   - \ref osThreadSetPriority : \copybrief osThreadSetPriority
   - \ref osThreadSuspend : \copybrief osThreadSuspend
   - \ref osThreadTerminate : \copybrief osThreadTerminate
   - \ref osThreadYield : \copybrief osThreadYield

 - \ref CMSIS_RTOS_ThreadFlagsMgmt
   - \ref osThreadFlagsSet : \copybrief osThreadFlagsSet
   - \ref osThreadFlagsClear : \copybrief osThreadFlagsClear
   - \ref osThreadFlagsGet : \copybrief osThreadFlagsGet
   - \ref osThreadFlagsWait : \copybrief osThreadFlagsWait

 - \ref CMSIS_RTOS_EventFlags
   - \ref osEventFlagsGetName : \copybrief osEventFlagsGetName
   - \ref osEventFlagsNew : \copybrief osEventFlagsNew
   - \ref osEventFlagsDelete : \copybrief osEventFlagsDelete
   - \ref osEventFlagsSet : \copybrief osEventFlagsSet
   - \ref osEventFlagsClear : \copybrief osEventFlagsClear
   - \ref osEventFlagsGet : \copybrief osEventFlagsGet
   - \ref osEventFlagsWait : \copybrief osEventFlagsWait

 - \ref CMSIS_RTOS_Wait
   - \ref osDelay : \copybrief osDelay
   - \ref osDelayUntil : \copybrief osDelayUntil

 - \ref CMSIS_RTOS_TimerMgmt
   - \ref osTimerDelete : \copybrief osTimerDelete
   - \ref osTimerGetName : \copybrief osTimerGetName
   - \ref osTimerIsRunning : \copybrief osTimerIsRunning
   - \ref osTimerNew : \copybrief osTimerNew
   - \ref osTimerStart : \copybrief osTimerStart
   - \ref osTimerStop : \copybrief osTimerStop

 - \ref CMSIS_RTOS_MutexMgmt
   - \ref osMutexAcquire : \copybrief osMutexAcquire
   - \ref osMutexDelete : \copybrief osMutexDelete
   - \ref osMutexGetName : \copybrief osMutexGetName
   - \ref osMutexGetOwner : \copybrief osMutexGetOwner
   - \ref osMutexNew : \copybrief osMutexNew
   - \ref osMutexRelease : \copybrief osMutexRelease

 - \ref CMSIS_RTOS_SemaphoreMgmt
   - \ref osSemaphoreAcquire : \copybrief osSemaphoreAcquire
   - \ref osSemaphoreDelete : \copybrief osSemaphoreDelete
   - \ref osSemaphoreGetCount : \copybrief osSemaphoreGetCount
   - \ref osSemaphoreGetName : \copybrief osSemaphoreGetName
   - \ref osSemaphoreNew : \copybrief osSemaphoreNew
   - \ref osSemaphoreRelease : \copybrief osSemaphoreRelease

 - \ref CMSIS_RTOS_PoolMgmt
   - \ref osMemoryPoolAlloc : \copybrief osMemoryPoolAlloc
   - \ref osMemoryPoolDelete : \copybrief osMemoryPoolDelete
   - \ref osMemoryPoolFree : \copybrief osMemoryPoolFree
   - \ref osMemoryPoolGetBlockSize : \copybrief osMemoryPoolGetBlockSize
   - \ref osMemoryPoolGetCapacity : \copybrief osMemoryPoolGetCapacity
   - \ref osMemoryPoolGetCount : \copybrief osMemoryPoolGetCount
   - \ref osMemoryPoolGetName : \copybrief osMemoryPoolGetName
   - \ref osMemoryPoolGetSpace : \copybrief osMemoryPoolGetSpace
   - \ref osMemoryPoolNew : \copybrief osMemoryPoolNew

 - \ref CMSIS_RTOS_Message
   - \ref osMessageQueueDelete : \copybrief osMessageQueueDelete
   - \ref osMessageQueueGet : \copybrief osMessageQueueGet
   - \ref osMessageQueueGetCapacity : \copybrief osMessageQueueGetCapacity
   - \ref osMessageQueueGetCount : \copybrief osMessageQueueGetCount
   - \ref osMessageQueueGetMsgSize : \copybrief osMessageQueueGetMsgSize
   - \ref osMessageQueueGetName : \copybrief osMessageQueueGetName
   - \ref osMessageQueueGetSpace : \copybrief osMessageQueueGetSpace
   - \ref osMessageQueueNew : \copybrief osMessageQueueNew
   - \ref osMessageQueuePut : \copybrief osMessageQueuePut
   - \ref osMessageQueueReset : \copybrief osMessageQueueReset
 
\todo restructure
 - \ref rtx5_specific
   - \ref osRtxErrorNotify : \copybrief osRtxErrorNotify
   - \ref osRtxIdleThread : \copybrief osRtxIdleThread

The following CMSIS-RTOS C API v2 functions can be called from threads and \ref CMSIS_RTOS_ISR_Calls "Interrupt Service Routines"
(ISR):
   - \ref osKernelGetInfo, \ref osKernelGetState,
     \ref osKernelGetTickCount, \ref osKernelGetTickFreq, \ref osKernelGetSysTimerCount, \ref osKernelGetSysTimerFreq
   - \ref osThreadGetId, \ref osThreadFlagsSet
   - \ref osEventFlagsSet, \ref osEventFlagsClear, \ref osEventFlagsGet, \ref osEventFlagsWait
   - \ref osSemaphoreAcquire, \ref osSemaphoreRelease, \ref osSemaphoreGetCount
   - \ref osMemoryPoolAlloc, \ref osMemoryPoolFree, \ref osMemoryPoolGetCapacity, \ref osMemoryPoolGetBlockSize,
     \ref osMemoryPoolGetCount, \ref osMemoryPoolGetSpace
   - \ref osMessageQueuePut, \ref osMessageQueueGet, \ref osMessageQueueGetCapacity, \ref osMessageQueueGetMsgSize,
     \ref osMessageQueueGetCount, \ref osMessageQueueGetSpace
*/


/*=======0=========1=========2=========3=========4=========5=========6=========7=========8=========9=========0=========1====*/
/**
\page rtos_apicpp CMSIS-RTOS C++ API

A C++11/C++14 interface is planned for the future.
*/

/*=======0=========1=========2=========3=========4=========5=========6=========7=========8=========9=========0=========1====*/
/**
\page rtos_os_tick_api OS Tick API

The CMSIS OS Tick API may be used by an RTOS implementation to be easily potable across the different Cortex-M and Cortex-A processors.
It provides a generic interface to a kernel system tick timer and defines the following functions:

 - The Reference for \ref CMSIS_RTOS_TickAPI provides details about these functions:
   - \ref OS_Tick_Setup : \copybrief OS_Tick_Setup
   - \ref OS_Tick_Enable : \copybrief OS_Tick_Enable
   - \ref OS_Tick_Disable : \copybrief OS_Tick_Disable
   - \ref OS_Tick_AcknowledgeIRQ : \copybrief OS_Tick_AcknowledgeIRQ
   - \ref OS_Tick_GetIRQn : \copybrief OS_Tick_GetIRQn
   - \ref OS_Tick_GetClock : \copybrief OS_Tick_GetClock
   - \ref OS_Tick_GetInterval : \copybrief OS_Tick_GetInterval
   - \ref OS_Tick_GetCount : \copybrief OS_Tick_GetCount
   - \ref OS_Tick_GetOverflow : \copybrief OS_Tick_GetOverflow

*/


/* ======================================================================================================================== */
// Group creation for Reference 
/* 
\addtogroup CMSIS_RTOS1 CMSIS-RTOS API v1
\brief This section describes the CMSIS-RTOS API v1. 
\details 
The CMSIS-RTOS is a generic API layer that interfaces to an existing RTOS kernel.

CMSIS-RTOS2 provides an translation layer for the
<a class="el" href="../../RTOS/html/index.html">CMSIS-RTOS API v1</a> that simplifies migration.

Refer to the <a class="el" href="../../RTOS/html/modules.html">Reference</a> guide of the CMSIS-RTOS API v1 for details.
*/

// Group creation for Reference 
/** 
\addtogroup CMSIS_RTOS CMSIS-RTOS API v2
\brief C interface of \ref rtos_api2 defined in cmsis_os2.h
\details 
The CMSIS-RTOS2 is a generic API layer that interfaces to an RTOS kernel.

The complete API interface is defined in the \ref cmsis_os2_h. When using dynamic memory allocation for objects, source code
or libraries require no modifications when using on a different CMSIS-RTOS2 implementation.

Refer to \ref rtos_api2_basics for further details.
*/

/**
\addtogroup CMSIS_RTOS_MemoryMgmt Memory Management
\ingroup CMSIS_RTOS
\brief Information about memory management possibilities
\details
The \ref CMSIS_RTOS offers two options for memory management the user can choose. For object storage one can either use
 - \ref CMSIS_RTOS_MemoryMgmt_Automatic (fully portable), or
 - \ref CMSIS_RTOS_MemoryMgmt_Manual (implementation specific).
 
In order to affect the memory allocation scheme all RTOS objects that can be created on request, i.e. those having a `osXxxNew`
function, accept an optional `osXxxAttr_t attr` argument on creation. As a rule of thumb the object attributes at least have
members to assign custom control block memory, i.e. `cb_mem` and `cb_size` members. By default, i.e. `attr` is `NULL`
or `cb_mem` is `NULL`, \ref CMSIS_RTOS_MemoryMgmt_Automatic is used. Providing a pointer to user memory in `cb_mem` switches
to \ref CMSIS_RTOS_MemoryMgmt_Manual.

\note For detailed information about memory allocation strategies provided in RTX5 refer to \ref MemoryAllocation.

\section CMSIS_RTOS_MemoryMgmt_Automatic Automatic Dynamic Allocation

The automatic allocation is the default and viable for many use-cases. Moreover it is fully portable across different
implementations of the \ref CMSIS_RTOS. The common drawback of dynamic memory allocation is the possibility of memory
fragmentation and exhaustion. Given that all needed objects are created once upon system initialization and never
deleted at runtime this class of runtime failures can be prevented, though.

The actual allocation strategy used is implementation specific, i.e. whether global heap or preallocated memory pools are used.

<b> Code Example:</b> 
\code{.c}
#include "cmsis_os2.h"                          // implementation agnostic
  
osMutexId_t mutex_id;
osMutexId_t mutex2_id;
  
const osMutexAttr_t Thread_Mutex_attr = {
  "myThreadMutex",                              // human readable mutex name
  osMutexRecursive | osMutexPrioInherit,        // attr_bits
  NULL,                                         // memory for control block (default)
  0U                                            // size for control block (default)
};
  
void CreateMutex (void)  {
  mutex_id = osMutexNew(NULL);                  // use default values for all attributes
  mutex2_id = osMutexNew(&Thread_Mutex_attr);   // use attributes from defined structure
  :
}
\endcode

The Mutexes in this example are created using automatic memory allocation.

\section CMSIS_RTOS_MemoryMgmt_Manual Manual User-defined Allocation

One can get fine grained control over memory allocation by providing user-defined memory.
The actual requirements such user-defined memory are implementation specific. Thus one
needs to carefully refer to the size and alignment rules of the implementation used, e.g.
for RTX see \ref StaticObjectMemory.

<b> Code Example:</b> 
\code{.c}
#include "rtx_os.h"                             // implementation specific
  
osMutexId_t mutex_id;
  
static uint32_t mutex_cb[osRtxMutexCbSize/4U];  // implementation specific
  
const osMutexAttr_t Thread_Mutex_attr = {
  "myThreadMutex",                              // human readable mutex name
  osMutexRecursive | osMutexPrioInherit,        // attr_bits
  mutex_cb,                                     // memory for control block (user-defined)
  sizeof(mutex_cb)                              // size for control block (user-defined)
};
  
void CreateMutex (void)  {
  mutex_id = osMutexNew(&Thread_Mutex_attr);    // use attributes from defined structure
  :
}
\endcode

The above example uses user-defined memory for the mutex control block. Depending on the actual
implementation used one needs to include the specific header file, `rtx_os.h` in this case.

*/

// Group creation for Reference 
/** 
\addtogroup CMSIS_RTOS CMSIS-RTOS API v2
\brief C interface of \ref rtos_api2 defined in <b>%cmsis_os2.h</b>
\details 
The CMSIS-RTOS2 is a generic API layer that interfaces to an RTOS kernel.

The complete API interface is defined in the \ref cmsis_os2_h. When using dynamic memory allocation for objects, source code
or libraries require no modifications when using on a different CMSIS-RTOS2 implementation.

Refer to \ref rtos_api2_basics for further details.
*/