2 * FreeRTOS Kernel V10.1.1
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30 * This project contains an application demonstrating the use of the
31 * FreeRTOS.org mini real time scheduler on the Luminary Micro LM3S811 Eval
32 * board. See http://www.FreeRTOS.org for more information.
34 * main() simply sets up the hardware, creates all the demo application tasks,
35 * then starts the scheduler. http://www.freertos.org/a00102.html provides
36 * more information on the standard demo tasks.
38 * In addition to a subset of the standard demo application tasks, main.c also
39 * defines the following tasks:
41 * + A 'Print' task. The print task is the only task permitted to access the
42 * LCD - thus ensuring mutual exclusion and consistent access to the resource.
43 * Other tasks do not access the LCD directly, but instead send the text they
44 * wish to display to the print task. The print task spends most of its time
45 * blocked - only waking when a message is queued for display.
47 * + A 'Button handler' task. The eval board contains a user push button that
48 * is configured to generate interrupts. The interrupt handler uses a
49 * semaphore to wake the button handler task - demonstrating how the priority
50 * mechanism can be used to defer interrupt processing to the task level. The
51 * button handler task sends a message both to the LCD (via the print task) and
52 * the UART where it can be viewed using a dumb terminal (via the UART to USB
53 * converter on the eval board). NOTES: The dumb terminal must be closed in
54 * order to reflash the microcontroller. A very basic interrupt driven UART
55 * driver is used that does not use the FIFO. 19200 baud is used.
57 * + A 'check' task. The check task only executes every five seconds but has a
58 * high priority so is guaranteed to get processor time. Its function is to
59 * check that all the other tasks are still operational and that no errors have
60 * been detected at any time. If no errors have every been detected 'PASS' is
61 * written to the display (via the print task) - if an error has ever been
62 * detected the message is changed to 'FAIL'. The position of the message is
63 * changed for each write.
68 /* Environment includes. */
69 #include "DriverLib.h"
71 /* Scheduler includes. */
77 /* Demo app includes. */
83 /* Delay between cycles of the 'check' task. */
84 #define mainCHECK_DELAY ( ( TickType_t ) 5000 / portTICK_PERIOD_MS )
86 /* UART configuration - note this does not use the FIFO so is not very
88 #define mainBAUD_RATE ( 19200 )
89 #define mainFIFO_SET ( 0x10 )
91 /* Demo task priorities. */
92 #define mainQUEUE_POLL_PRIORITY ( tskIDLE_PRIORITY + 2 )
93 #define mainCHECK_TASK_PRIORITY ( tskIDLE_PRIORITY + 3 )
94 #define mainSEM_TEST_PRIORITY ( tskIDLE_PRIORITY + 1 )
95 #define mainBLOCK_Q_PRIORITY ( tskIDLE_PRIORITY + 2 )
97 /* Demo board specifics. */
98 #define mainPUSH_BUTTON GPIO_PIN_4
101 #define mainQUEUE_SIZE ( 3 )
102 #define mainDEBOUNCE_DELAY ( ( TickType_t ) 150 / portTICK_PERIOD_MS )
103 #define mainNO_DELAY ( ( TickType_t ) 0 )
105 * Configure the processor and peripherals for this demo.
107 static void prvSetupHardware( void );
110 * The 'check' task, as described at the top of this file.
112 static void vCheckTask( void *pvParameters );
115 * The task that is woken by the ISR that processes GPIO interrupts originating
116 * from the push button.
118 static void vButtonHandlerTask( void *pvParameters );
121 * The task that controls access to the LCD.
123 static void vPrintTask( void *pvParameter );
125 /* String that is transmitted on the UART. */
126 static char *cMessage = "Task woken by button interrupt! --- ";
127 static volatile char *pcNextChar;
129 /* The semaphore used to wake the button handler task from within the GPIO
130 interrupt handler. */
131 SemaphoreHandle_t xButtonSemaphore;
133 /* The queue used to send strings to the print task for display on the LCD. */
134 QueueHandle_t xPrintQueue;
136 /* Newer library version. */
137 extern void UARTConfigSetExpClk(unsigned long ulBase, unsigned long ulUARTClk, unsigned long ulBaud, unsigned long ulConfig);
138 /*-----------------------------------------------------------*/
142 /* Configure the clocks, UART and GPIO. */
145 /* Create the semaphore used to wake the button handler task from the GPIO
147 vSemaphoreCreateBinary( xButtonSemaphore );
148 xSemaphoreTake( xButtonSemaphore, 0 );
150 /* Create the queue used to pass message to vPrintTask. */
151 xPrintQueue = xQueueCreate( mainQUEUE_SIZE, sizeof( char * ) );
153 /* Start the standard demo tasks. */
154 vStartIntegerMathTasks( tskIDLE_PRIORITY );
155 vStartPolledQueueTasks( mainQUEUE_POLL_PRIORITY );
156 vStartSemaphoreTasks( mainSEM_TEST_PRIORITY );
157 vStartBlockingQueueTasks( mainBLOCK_Q_PRIORITY );
159 /* Start the tasks defined within the file. */
160 xTaskCreate( vCheckTask, "Check", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY, NULL );
161 xTaskCreate( vButtonHandlerTask, "Status", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY + 1, NULL );
162 xTaskCreate( vPrintTask, "Print", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY - 1, NULL );
164 /* Start the scheduler. */
165 vTaskStartScheduler();
167 /* Will only get here if there was insufficient heap to start the
172 /*-----------------------------------------------------------*/
174 static void vCheckTask( void *pvParameters )
176 portBASE_TYPE xErrorOccurred = pdFALSE;
177 TickType_t xLastExecutionTime;
178 const char *pcPassMessage = "PASS";
179 const char *pcFailMessage = "FAIL";
181 /* Initialise xLastExecutionTime so the first call to vTaskDelayUntil()
183 xLastExecutionTime = xTaskGetTickCount();
187 /* Perform this check every mainCHECK_DELAY milliseconds. */
188 vTaskDelayUntil( &xLastExecutionTime, mainCHECK_DELAY );
190 /* Has an error been found in any task? */
192 if( xAreIntegerMathsTaskStillRunning() != pdTRUE )
194 xErrorOccurred = pdTRUE;
197 if( xArePollingQueuesStillRunning() != pdTRUE )
199 xErrorOccurred = pdTRUE;
202 if( xAreSemaphoreTasksStillRunning() != pdTRUE )
204 xErrorOccurred = pdTRUE;
207 if( xAreBlockingQueuesStillRunning() != pdTRUE )
209 xErrorOccurred = pdTRUE;
212 /* Send either a pass or fail message. If an error is found it is
213 never cleared again. We do not write directly to the LCD, but instead
214 queue a message for display by the print task. */
215 if( xErrorOccurred == pdTRUE )
217 xQueueSend( xPrintQueue, &pcFailMessage, portMAX_DELAY );
221 xQueueSend( xPrintQueue, &pcPassMessage, portMAX_DELAY );
225 /*-----------------------------------------------------------*/
227 static void prvSetupHardware( void )
230 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
232 /* Setup the push button. */
233 SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
234 GPIODirModeSet(GPIO_PORTC_BASE, mainPUSH_BUTTON, GPIO_DIR_MODE_IN);
235 GPIOIntTypeSet( GPIO_PORTC_BASE, mainPUSH_BUTTON,GPIO_FALLING_EDGE );
236 IntPrioritySet( INT_GPIOC, configKERNEL_INTERRUPT_PRIORITY );
237 GPIOPinIntEnable( GPIO_PORTC_BASE, mainPUSH_BUTTON );
238 IntEnable( INT_GPIOC );
242 /* Enable the UART. */
243 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
244 SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
246 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
248 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
250 /* Configure the UART for 8-N-1 operation. */
251 UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
253 /* We don't want to use the fifo. This is for test purposes to generate
254 as many interrupts as possible. */
255 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
257 /* Enable Tx interrupts. */
258 HWREG( UART0_BASE + UART_O_IM ) |= UART_INT_TX;
259 IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
260 IntEnable( INT_UART0 );
263 /* Initialise the LCD> */
265 OSRAMStringDraw("www.FreeRTOS.org", 0, 0);
266 OSRAMStringDraw("LM3S811 demo", 16, 1);
268 /*-----------------------------------------------------------*/
270 static void vButtonHandlerTask( void *pvParameters )
272 const char *pcInterruptMessage = "Int";
276 /* Wait for a GPIO interrupt to wake this task. */
277 while( xSemaphoreTake( xButtonSemaphore, portMAX_DELAY ) != pdPASS );
279 /* Start the Tx of the message on the UART. */
280 UARTIntDisable( UART0_BASE, UART_INT_TX );
282 pcNextChar = cMessage;
284 /* Send the first character. */
285 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
287 HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
292 UARTIntEnable(UART0_BASE, UART_INT_TX);
294 /* Queue a message for the print task to display on the LCD. */
295 xQueueSend( xPrintQueue, &pcInterruptMessage, portMAX_DELAY );
297 /* Make sure we don't process bounces. */
298 vTaskDelay( mainDEBOUNCE_DELAY );
299 xSemaphoreTake( xButtonSemaphore, mainNO_DELAY );
303 /*-----------------------------------------------------------*/
307 unsigned long ulStatus;
309 /* What caused the interrupt. */
310 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
312 /* Clear the interrupt. */
313 UARTIntClear( UART0_BASE, ulStatus );
315 /* Was a Tx interrupt pending? */
316 if( ulStatus & UART_INT_TX )
318 /* Send the next character in the string. We are not using the FIFO. */
319 if( *pcNextChar != NULL )
321 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
323 HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
329 /*-----------------------------------------------------------*/
331 void vGPIO_ISR( void )
333 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
335 /* Clear the interrupt. */
336 GPIOPinIntClear( GPIO_PORTC_BASE, mainPUSH_BUTTON );
338 /* Wake the button handler task. */
339 xSemaphoreGiveFromISR( xButtonSemaphore, &xHigherPriorityTaskWoken );
340 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
342 /*-----------------------------------------------------------*/
344 static void vPrintTask( void *pvParameters )
347 unsigned portBASE_TYPE uxLine = 0, uxRow = 0;
351 /* Wait for a message to arrive. */
352 xQueueReceive( xPrintQueue, &pcMessage, portMAX_DELAY );
354 /* Write the message to the LCD. */
358 OSRAMStringDraw( pcMessage, uxLine & 0x3f, uxRow & 0x01);