/* | |
FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* If you are: * | |
* * | |
* + New to FreeRTOS, * | |
* + Wanting to learn FreeRTOS or multitasking in general quickly * | |
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* * | |
* then take a look at the FreeRTOS books - available as PDF or paperback * | |
* * | |
* "Using the FreeRTOS Real Time Kernel - a Practical Guide" * | |
* http://www.FreeRTOS.org/Documentation * | |
* * | |
* A pdf reference manual is also available. Both are usually delivered * | |
* to your inbox within 20 minutes to two hours when purchased between 8am * | |
* and 8pm GMT (although please allow up to 24 hours in case of * | |
* exceptional circumstances). Thank you for your support! * | |
* * | |
*************************************************************************** | |
This file is part of the FreeRTOS distribution. | |
FreeRTOS is free software; you can redistribute it and/or modify it under | |
the terms of the GNU General Public License (version 2) as published by the | |
Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
***NOTE*** The exception to the GPL is included to allow you to distribute | |
a combined work that includes FreeRTOS without being obliged to provide the | |
source code for proprietary components outside of the FreeRTOS kernel. | |
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT | |
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/* | |
This simple demo project runs on the STM32 Discovery board, which is | |
populated with an STM32F100RB Cortex-M3 microcontroller. The discovery board | |
makes an ideal low cost evaluation platform, but the 8K of RAM provided on the | |
STM32F100RB does not allow the simple application to demonstrate all of all the | |
FreeRTOS kernel features. Therefore, this simple demo only actively | |
demonstrates task, queue, timer and interrupt functionality. In addition, the | |
demo is configured to include malloc failure, idle and stack overflow hook | |
functions. | |
The idle hook function: | |
The idle hook function queries the amount of FreeRTOS heap space that is | |
remaining (see vApplicationIdleHook() defined in this file). The demo | |
application is configured use 7K or the available 8K of RAM as the FreeRTOS heap. | |
Memory is only allocated from this heap during initialisation, and this demo | |
only actually uses 1.6K bytes of the configured 7K available - leaving 5.4K | |
bytes of heap space unallocated. | |
The main() Function: | |
main() creates one software timer, one queue, and two tasks. It then starts the | |
scheduler. | |
The Queue Send Task: | |
The queue send task is implemented by the prvQueueSendTask() function in this | |
file. prvQueueSendTask() sits in a loop that causes it to repeatedly block for | |
200 milliseconds, before sending the value 100 to the queue that was created | |
within main(). Once the value is sent, the task loops back around to block for | |
another 200 milliseconds. | |
The Queue Receive Task: | |
The queue receive task is implemented by the prvQueueReceiveTask() function | |
in this file. prvQueueReceiveTask() sits in a loop that causes repeatedly | |
attempt to read data from the queue that was created within main(). When data | |
is received, the task checks the value of the data, and if the value equals | |
the expected 100, toggles the green LED. The 'block time' parameter passed to | |
the queue receive function specifies that the task should be held in the Blocked | |
state indefinitely to wait for data to be available on the queue. The queue | |
receive task will only leave the Blocked state when the queue send task writes | |
to the queue. As the queue send task writes to the queue every 200 | |
milliseconds, the queue receive task leaves the Blocked state every 200 | |
milliseconds, and therefore toggles the green LED every 200 milliseconds. | |
The LED Software Timer and the Button Interrupt: | |
The user button B1 is configured to generate an interrupt each time it is | |
pressed. The interrupt service routine switches the red LED on, and resets the | |
LED software timer. The LED timer has a 5000 millisecond (5 second) period, and | |
uses a callback function that is defined to just turn the red LED off. | |
Therefore, pressing the user button will turn the red LED on, and the LED will | |
remain on until a full five seconds pass without the button being pressed. | |
*/ | |
/* Kernel includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "queue.h" | |
#include "timers.h" | |
/* Microsemi drivers/libraries. */ | |
#include "mss_gpio.h" | |
#include "mss_watchdog.h" | |
/* Priorities at which the tasks are created. */ | |
#define mainQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 ) | |
#define mainQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 ) | |
/* The rate at which data is sent to the queue, specified in milliseconds, and | |
converted to ticks using the portTICK_RATE_MS constant. */ | |
#define mainQUEUE_SEND_FREQUENCY_MS ( 200 / portTICK_RATE_MS ) | |
/* The number of items the queue can hold. This is 1 as the receive task | |
will remove items as they are added, meaning the send task should always find | |
the queue empty. */ | |
#define mainQUEUE_LENGTH ( 1 ) | |
#define mainTASK_CONTROLLED_LED 0x01UL | |
#define mainTIMER_CONTROLLED_LED 0x02UL | |
/*-----------------------------------------------------------*/ | |
/* | |
* Setup the NVIC, LED outputs, and button inputs. | |
*/ | |
static void prvSetupHardware( void ); | |
/* | |
* The tasks as described in the comments at the top of this file. | |
*/ | |
static void prvQueueReceiveTask( void *pvParameters ); | |
static void prvQueueSendTask( void *pvParameters ); | |
/* | |
* The LED timer callback function. This does nothing but switch the red LED | |
* off. | |
*/ | |
static void vLEDTimerCallback( xTimerHandle xTimer ); | |
/*-----------------------------------------------------------*/ | |
/* The queue used by both tasks. */ | |
static xQueueHandle xQueue = NULL; | |
/* The LED software timer. This uses vLEDTimerCallback() as its callback | |
function. */ | |
static xTimerHandle xLEDTimer = NULL; | |
volatile unsigned long ulGPIOState = 0UL; | |
/*-----------------------------------------------------------*/ | |
int main(void) | |
{ | |
/* Configure the NVIC, LED outputs and button inputs. */ | |
prvSetupHardware(); | |
/* Create the queue. */ | |
xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) ); | |
if( xQueue != NULL ) | |
{ | |
/* Start the two tasks as described in the comments at the top of this | |
file. */ | |
xTaskCreate( prvQueueReceiveTask, ( signed char * ) "Rx", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_RECEIVE_TASK_PRIORITY, NULL ); | |
xTaskCreate( prvQueueSendTask, ( signed char * ) "TX", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_SEND_TASK_PRIORITY, NULL ); | |
/* Create the software timer that is responsible for turning off the LED | |
if the button is not pushed within 5000ms, as described at the top of | |
this file. */ | |
xLEDTimer = xTimerCreate( ( const signed char * ) "LEDTimer", /* A text name, purely to help debugging. */ | |
( 5000 / portTICK_RATE_MS ), /* The timer period, in this case 5000ms (5s). */ | |
pdFALSE, /* This is a one shot timer, so xAutoReload is set to pdFALSE. */ | |
( void * ) 0, /* The ID is not used, so can be set to anything. */ | |
vLEDTimerCallback /* The callback function that switches the LED off. */ | |
); | |
/* Start the tasks and timer running. */ | |
vTaskStartScheduler(); | |
} | |
/* If all is well, the scheduler will now be running, and the following line | |
will never be reached. If the following line does execute, then there was | |
insufficient FreeRTOS heap memory available for the idle and/or timer tasks | |
to be created. See the memory management section on the FreeRTOS web site | |
for more details. */ | |
for( ;; ); | |
} | |
/*-----------------------------------------------------------*/ | |
static void vLEDTimerCallback( xTimerHandle xTimer ) | |
{ | |
/* The timer has expired - so no button pushes have occurred in the last | |
five seconds - turn the LED off. NOTE - accessing the LED port should use | |
a critical section because it is accessed from multiple tasks, and the | |
button interrupt - in this trivial case, for simplicity, the critical | |
section is omitted. */ | |
ulGPIOState |= mainTIMER_CONTROLLED_LED; | |
MSS_GPIO_set_outputs( ulGPIOState ); | |
} | |
/*-----------------------------------------------------------*/ | |
/* The ISR executed when the user button is pushed. */ | |
void GPIO8_IRQHandler( void ) | |
{ | |
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; | |
/* The button was pushed, so ensure the LED is on before resetting the | |
LED timer. The LED timer will turn the LED off if the button is not | |
pushed within 5000ms. */ | |
ulGPIOState &= ~mainTIMER_CONTROLLED_LED; | |
MSS_GPIO_set_outputs( ulGPIOState ); | |
/* This interrupt safe FreeRTOS function can be called from this interrupt | |
because the interrupt priority is below the | |
configMAX_SYSCALL_INTERRUPT_PRIORITY setting in FreeRTOSConfig.h. */ | |
xTimerResetFromISR( xLEDTimer, &xHigherPriorityTaskWoken ); | |
/* Clear the interrupt before leaving. */ | |
MSS_GPIO_clear_irq( MSS_GPIO_8 ); | |
/* If calling xTimerResetFromISR() caused a task (in this case the timer | |
service/daemon task) to unblock, and the unblocked task has a priority | |
higher than or equal to the task that was interrupted, then | |
xHigherPriorityTaskWoken will now be set to pdTRUE, and calling | |
portEND_SWITCHING_ISR() will ensure the unblocked task runs next. */ | |
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken ); | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvQueueSendTask( void *pvParameters ) | |
{ | |
portTickType xNextWakeTime; | |
const unsigned long ulValueToSend = 100UL; | |
/* Initialise xNextWakeTime - this only needs to be done once. */ | |
xNextWakeTime = xTaskGetTickCount(); | |
for( ;; ) | |
{ | |
/* Place this task in the blocked state until it is time to run again. | |
The block time is specified in ticks, the constant used converts ticks | |
to ms. While in the Blocked state this task will not consume any CPU | |
time. */ | |
vTaskDelayUntil( &xNextWakeTime, mainQUEUE_SEND_FREQUENCY_MS ); | |
/* Send to the queue - causing the queue receive task to unblock and | |
toggle an LED. 0 is used as the block time so the sending operation | |
will not block - it shouldn't need to block as the queue should always | |
be empty at this point in the code. */ | |
xQueueSend( xQueue, &ulValueToSend, 0 ); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvQueueReceiveTask( void *pvParameters ) | |
{ | |
unsigned long ulReceivedValue; | |
for( ;; ) | |
{ | |
/* Wait until something arrives in the queue - this task will block | |
indefinitely provided INCLUDE_vTaskSuspend is set to 1 in | |
FreeRTOSConfig.h. */ | |
xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY ); | |
/* To get here something must have been received from the queue, but | |
is it the expected value? If it is, toggle the green LED. */ | |
if( ulReceivedValue == 100UL ) | |
{ | |
/* NOTE - accessing the LED port should use a critical section | |
because it is accessed from multiple tasks, and the button interrupt | |
- in this trivial case, for simplicity, the critical section is | |
omitted. */ | |
if( ( ulGPIOState & mainTASK_CONTROLLED_LED ) != 0 ) | |
{ | |
ulGPIOState &= ~mainTASK_CONTROLLED_LED; | |
} | |
else | |
{ | |
ulGPIOState |= mainTASK_CONTROLLED_LED; | |
} | |
MSS_GPIO_set_outputs( ulGPIOState ); | |
} | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvSetupHardware( void ) | |
{ | |
/* Disable the Watch Dog Timer */ | |
MSS_WD_disable( ); | |
/* Initialise the GPIO */ | |
MSS_GPIO_init(); | |
/* Set up GPIO for the LEDs. */ | |
MSS_GPIO_config( MSS_GPIO_0 , MSS_GPIO_OUTPUT_MODE ); | |
MSS_GPIO_config( MSS_GPIO_1 , MSS_GPIO_OUTPUT_MODE ); | |
MSS_GPIO_config( MSS_GPIO_2 , MSS_GPIO_OUTPUT_MODE ); | |
MSS_GPIO_config( MSS_GPIO_3 , MSS_GPIO_OUTPUT_MODE ); | |
MSS_GPIO_config( MSS_GPIO_4 , MSS_GPIO_OUTPUT_MODE ); | |
MSS_GPIO_config( MSS_GPIO_5 , MSS_GPIO_OUTPUT_MODE ); | |
MSS_GPIO_config( MSS_GPIO_6 , MSS_GPIO_OUTPUT_MODE ); | |
MSS_GPIO_config( MSS_GPIO_7 , MSS_GPIO_OUTPUT_MODE ); | |
/* All LEDs start off. */ | |
ulGPIOState = 0xffffffffUL; | |
MSS_GPIO_set_outputs( ulGPIOState ); | |
/* Setup the GPIO and the NVIC for the switch used in this simple demo. */ | |
NVIC_EnableIRQ( GPIO8_IRQn ); | |
MSS_GPIO_config( MSS_GPIO_8, MSS_GPIO_INPUT_MODE | MSS_GPIO_IRQ_EDGE_NEGATIVE ); | |
MSS_GPIO_enable_irq( MSS_GPIO_8 ); | |
} | |
/*-----------------------------------------------------------*/ | |
void vApplicationMallocFailedHook( void ) | |
{ | |
/* Called if a call to pvPortMalloc() fails because there is insufficient | |
free memory available in the FreeRTOS heap. pvPortMalloc() is called | |
internally by FreeRTOS API functions that create tasks, queues, software | |
timers, and semaphores. The size of the FreeRTOS heap is set by the | |
configTOTAL_HEAP_SIZE configuration constant in FreeRTOSConfig.h. */ | |
for( ;; ); | |
} | |
/*-----------------------------------------------------------*/ | |
void vApplicationStackOverflowHook( xTaskHandle *pxTask, signed char *pcTaskName ) | |
{ | |
( void ) pcTaskName; | |
( void ) pxTask; | |
/* Run time stack overflow checking is performed if | |
configconfigCHECK_FOR_STACK_OVERFLOW is defined to 1 or 2. This hook | |
function is called if a stack overflow is detected. */ | |
for( ;; ); | |
} | |
/*-----------------------------------------------------------*/ | |
void vApplicationIdleHook( void ) | |
{ | |
volatile size_t xFreeStackSpace; | |
/* This function is called on each cycle of the idle task. In this case it | |
does nothing useful, other than report the amout of FreeRTOS heap that | |
remains unallocated. */ | |
xFreeStackSpace = xPortGetFreeHeapSize(); | |
if( xFreeStackSpace > 100 ) | |
{ | |
/* By now, the kernel has allocated everything it is going to, so | |
if there is a lot of heap remaining unallocated then | |
the value of configTOTAL_HEAP_SIZE in FreeRTOSConfig.h can be | |
reduced accordingly. */ | |
} | |
} |