Startup File startup_<device>.s (deprecated)

The Startup File startup_<device>.s (deprecated) contains:

• The reset handler which is executed after CPU reset and typically calls the SystemInit function.
• The setup values for the Main Stack Pointer (MSP).
• Exception vectors of the Cortex-M Processor with weak functions that implement default routines.
• Interrupt vectors that are device specific with weak functions that implement default routines.

The file exists for each supported toolchain and is the only tool-chain specific CMSIS file.

To adapt the file to a new device only the interrupt vector table needs to be extended with the device-specific interrupt handlers. The naming convention for the interrupt handler names are <interrupt_name>_IRQHandler. This table needs to be consistent with IRQn_Type that defines all the IRQ numbers for each interrupt.

Example:

The following example shows the extension of the interrupt vector table for the LPC1100 device family.

                ; External Interrupts
                DCD     WAKEUP0_IRQHandler       ; 16+ 0: Wakeup PIO0.0
                DCD     WAKEUP1_IRQHandler       ; 16+ 1: Wakeup PIO0.1
                DCD     WAKEUP2_IRQHandler       ; 16+ 2: Wakeup PIO0.2
                 :       :
                 :       :
                DCD     EINT1_IRQHandler         ; 16+30: PIO INT1
                DCD     EINT0_IRQHandler         ; 16+31: PIO INT0
   :
   :
                EXPORT  WAKEUP0_IRQHandler       [WEAK]
                EXPORT  WAKEUP1_IRQHandler       [WEAK]
                EXPORT  WAKEUP2_IRQHandler       [WEAK]
                 :       :
                 :       :
                EXPORT  EINT1_IRQHandler         [WEAK]
                EXPORT  EINT0_IRQHandler         [WEAK]
 
WAKEUP0_IRQHandler
WAKEUP1_IRQHandler
WAKEUP1_IRQHandler
      :
      :
EINT1_IRQHandler
EINT0_IRQHandler
                B       .

startup_Device.S Template File

An Arm Compiler V6 assembler startup_Device.S Template File for an Armv8-M processor like Cortex-M33 is shown below. The files for other compiler vendors differ slightly in the syntax, but not in the overall structure.