/* | |
FreeRTOS.org V5.3.0 - Copyright (C) 2003-2009 Richard Barry. | |
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*************************************************************************** | |
* * | |
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation * | |
* * | |
* This is a concise, step by step, 'hands on' guide that describes both * | |
* general multitasking concepts and FreeRTOS specifics. It presents and * | |
* explains numerous examples that are written using the FreeRTOS API. * | |
* Full source code for all the examples is provided in an accompanying * | |
* .zip file. * | |
* * | |
*************************************************************************** | |
1 tab == 4 spaces! | |
Please ensure to read the configuration and relevant port sections of the | |
online documentation. | |
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. | |
*/ | |
#ifndef INC_FREERTOS_H | |
#error "#include FreeRTOS.h" must appear in source files before "#include croutine.h" | |
#endif | |
#ifndef CO_ROUTINE_H | |
#define CO_ROUTINE_H | |
#include "list.h" | |
#ifdef __cplusplus | |
extern "C" { | |
#endif | |
/* Used to hide the implementation of the co-routine control block. The | |
control block structure however has to be included in the header due to | |
the macro implementation of the co-routine functionality. */ | |
typedef void * xCoRoutineHandle; | |
/* Defines the prototype to which co-routine functions must conform. */ | |
typedef void (*crCOROUTINE_CODE)( xCoRoutineHandle, unsigned portBASE_TYPE ); | |
typedef struct corCoRoutineControlBlock | |
{ | |
crCOROUTINE_CODE pxCoRoutineFunction; | |
xListItem xGenericListItem; /*< List item used to place the CRCB in ready and blocked queues. */ | |
xListItem xEventListItem; /*< List item used to place the CRCB in event lists. */ | |
unsigned portBASE_TYPE uxPriority; /*< The priority of the co-routine in relation to other co-routines. */ | |
unsigned portBASE_TYPE uxIndex; /*< Used to distinguish between co-routines when multiple co-routines use the same co-routine function. */ | |
unsigned portSHORT uxState; /*< Used internally by the co-routine implementation. */ | |
} corCRCB; /* Co-routine control block. Note must be identical in size down to uxPriority with tskTCB. */ | |
/** | |
* croutine. h | |
*<pre> | |
portBASE_TYPE xCoRoutineCreate( | |
crCOROUTINE_CODE pxCoRoutineCode, | |
unsigned portBASE_TYPE uxPriority, | |
unsigned portBASE_TYPE uxIndex | |
);</pre> | |
* | |
* Create a new co-routine and add it to the list of co-routines that are | |
* ready to run. | |
* | |
* @param pxCoRoutineCode Pointer to the co-routine function. Co-routine | |
* functions require special syntax - see the co-routine section of the WEB | |
* documentation for more information. | |
* | |
* @param uxPriority The priority with respect to other co-routines at which | |
* the co-routine will run. | |
* | |
* @param uxIndex Used to distinguish between different co-routines that | |
* execute the same function. See the example below and the co-routine section | |
* of the WEB documentation for further information. | |
* | |
* @return pdPASS if the co-routine was successfully created and added to a ready | |
* list, otherwise an error code defined with ProjDefs.h. | |
* | |
* Example usage: | |
<pre> | |
// Co-routine to be created. | |
void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
// Variables in co-routines must be declared static if they must maintain value across a blocking call. | |
// This may not be necessary for const variables. | |
static const char cLedToFlash[ 2 ] = { 5, 6 }; | |
static const portTickType xTimeToDelay[ 2 ] = { 200, 400 }; | |
// Must start every co-routine with a call to crSTART(); | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// This co-routine just delays for a fixed period, then toggles | |
// an LED. Two co-routines are created using this function, so | |
// the uxIndex parameter is used to tell the co-routine which | |
// LED to flash and how long to delay. This assumes xQueue has | |
// already been created. | |
vParTestToggleLED( cLedToFlash[ uxIndex ] ); | |
crDELAY( xHandle, uxFlashRates[ uxIndex ] ); | |
} | |
// Must end every co-routine with a call to crEND(); | |
crEND(); | |
} | |
// Function that creates two co-routines. | |
void vOtherFunction( void ) | |
{ | |
unsigned char ucParameterToPass; | |
xTaskHandle xHandle; | |
// Create two co-routines at priority 0. The first is given index 0 | |
// so (from the code above) toggles LED 5 every 200 ticks. The second | |
// is given index 1 so toggles LED 6 every 400 ticks. | |
for( uxIndex = 0; uxIndex < 2; uxIndex++ ) | |
{ | |
xCoRoutineCreate( vFlashCoRoutine, 0, uxIndex ); | |
} | |
} | |
</pre> | |
* \defgroup xCoRoutineCreate xCoRoutineCreate | |
* \ingroup Tasks | |
*/ | |
signed portBASE_TYPE xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, unsigned portBASE_TYPE uxPriority, unsigned portBASE_TYPE uxIndex ); | |
/** | |
* croutine. h | |
*<pre> | |
void vCoRoutineSchedule( void );</pre> | |
* | |
* Run a co-routine. | |
* | |
* vCoRoutineSchedule() executes the highest priority co-routine that is able | |
* to run. The co-routine will execute until it either blocks, yields or is | |
* preempted by a task. Co-routines execute cooperatively so one | |
* co-routine cannot be preempted by another, but can be preempted by a task. | |
* | |
* If an application comprises of both tasks and co-routines then | |
* vCoRoutineSchedule should be called from the idle task (in an idle task | |
* hook). | |
* | |
* Example usage: | |
<pre> | |
// This idle task hook will schedule a co-routine each time it is called. | |
// The rest of the idle task will execute between co-routine calls. | |
void vApplicationIdleHook( void ) | |
{ | |
vCoRoutineSchedule(); | |
} | |
// Alternatively, if you do not require any other part of the idle task to | |
// execute, the idle task hook can call vCoRoutineScheduler() within an | |
// infinite loop. | |
void vApplicationIdleHook( void ) | |
{ | |
for( ;; ) | |
{ | |
vCoRoutineSchedule(); | |
} | |
} | |
</pre> | |
* \defgroup vCoRoutineSchedule vCoRoutineSchedule | |
* \ingroup Tasks | |
*/ | |
void vCoRoutineSchedule( void ); | |
/** | |
* croutine. h | |
* <pre> | |
crSTART( xCoRoutineHandle xHandle );</pre> | |
* | |
* This macro MUST always be called at the start of a co-routine function. | |
* | |
* Example usage: | |
<pre> | |
// Co-routine to be created. | |
void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
// Variables in co-routines must be declared static if they must maintain value across a blocking call. | |
static portLONG ulAVariable; | |
// Must start every co-routine with a call to crSTART(); | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// Co-routine functionality goes here. | |
} | |
// Must end every co-routine with a call to crEND(); | |
crEND(); | |
}</pre> | |
* \defgroup crSTART crSTART | |
* \ingroup Tasks | |
*/ | |
#define crSTART( pxCRCB ) switch( ( ( corCRCB * )pxCRCB )->uxState ) { case 0: | |
/** | |
* croutine. h | |
* <pre> | |
crEND();</pre> | |
* | |
* This macro MUST always be called at the end of a co-routine function. | |
* | |
* Example usage: | |
<pre> | |
// Co-routine to be created. | |
void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
// Variables in co-routines must be declared static if they must maintain value across a blocking call. | |
static portLONG ulAVariable; | |
// Must start every co-routine with a call to crSTART(); | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// Co-routine functionality goes here. | |
} | |
// Must end every co-routine with a call to crEND(); | |
crEND(); | |
}</pre> | |
* \defgroup crSTART crSTART | |
* \ingroup Tasks | |
*/ | |
#define crEND() } | |
/* | |
* These macros are intended for internal use by the co-routine implementation | |
* only. The macros should not be used directly by application writers. | |
*/ | |
#define crSET_STATE0( xHandle ) ( ( corCRCB * )xHandle)->uxState = (__LINE__ * 2); return; case (__LINE__ * 2): | |
#define crSET_STATE1( xHandle ) ( ( corCRCB * )xHandle)->uxState = ((__LINE__ * 2)+1); return; case ((__LINE__ * 2)+1): | |
/** | |
* croutine. h | |
*<pre> | |
crDELAY( xCoRoutineHandle xHandle, portTickType xTicksToDelay );</pre> | |
* | |
* Delay a co-routine for a fixed period of time. | |
* | |
* crDELAY can only be called from the co-routine function itself - not | |
* from within a function called by the co-routine function. This is because | |
* co-routines do not maintain their own stack. | |
* | |
* @param xHandle The handle of the co-routine to delay. This is the xHandle | |
* parameter of the co-routine function. | |
* | |
* @param xTickToDelay The number of ticks that the co-routine should delay | |
* for. The actual amount of time this equates to is defined by | |
* configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant portTICK_RATE_MS | |
* can be used to convert ticks to milliseconds. | |
* | |
* Example usage: | |
<pre> | |
// Co-routine to be created. | |
void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
// Variables in co-routines must be declared static if they must maintain value across a blocking call. | |
// This may not be necessary for const variables. | |
// We are to delay for 200ms. | |
static const xTickType xDelayTime = 200 / portTICK_RATE_MS; | |
// Must start every co-routine with a call to crSTART(); | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// Delay for 200ms. | |
crDELAY( xHandle, xDelayTime ); | |
// Do something here. | |
} | |
// Must end every co-routine with a call to crEND(); | |
crEND(); | |
}</pre> | |
* \defgroup crDELAY crDELAY | |
* \ingroup Tasks | |
*/ | |
#define crDELAY( xHandle, xTicksToDelay ) \ | |
if( xTicksToDelay > 0 ) \ | |
{ \ | |
vCoRoutineAddToDelayedList( xTicksToDelay, NULL ); \ | |
} \ | |
crSET_STATE0( xHandle ); | |
/** | |
* <pre> | |
crQUEUE_SEND( | |
xCoRoutineHandle xHandle, | |
xQueueHandle pxQueue, | |
void *pvItemToQueue, | |
portTickType xTicksToWait, | |
portBASE_TYPE *pxResult | |
)</pre> | |
* | |
* The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine | |
* equivalent to the xQueueSend() and xQueueReceive() functions used by tasks. | |
* | |
* crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas | |
* xQueueSend() and xQueueReceive() can only be used from tasks. | |
* | |
* crQUEUE_SEND can only be called from the co-routine function itself - not | |
* from within a function called by the co-routine function. This is because | |
* co-routines do not maintain their own stack. | |
* | |
* See the co-routine section of the WEB documentation for information on | |
* passing data between tasks and co-routines and between ISR's and | |
* co-routines. | |
* | |
* @param xHandle The handle of the calling co-routine. This is the xHandle | |
* parameter of the co-routine function. | |
* | |
* @param pxQueue The handle of the queue on which the data will be posted. | |
* The handle is obtained as the return value when the queue is created using | |
* the xQueueCreate() API function. | |
* | |
* @param pvItemToQueue A pointer to the data being posted onto the queue. | |
* The number of bytes of each queued item is specified when the queue is | |
* created. This number of bytes is copied from pvItemToQueue into the queue | |
* itself. | |
* | |
* @param xTickToDelay The number of ticks that the co-routine should block | |
* to wait for space to become available on the queue, should space not be | |
* available immediately. The actual amount of time this equates to is defined | |
* by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant | |
* portTICK_RATE_MS can be used to convert ticks to milliseconds (see example | |
* below). | |
* | |
* @param pxResult The variable pointed to by pxResult will be set to pdPASS if | |
* data was successfully posted onto the queue, otherwise it will be set to an | |
* error defined within ProjDefs.h. | |
* | |
* Example usage: | |
<pre> | |
// Co-routine function that blocks for a fixed period then posts a number onto | |
// a queue. | |
static void prvCoRoutineFlashTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
// Variables in co-routines must be declared static if they must maintain value across a blocking call. | |
static portBASE_TYPE xNumberToPost = 0; | |
static portBASE_TYPE xResult; | |
// Co-routines must begin with a call to crSTART(). | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// This assumes the queue has already been created. | |
crQUEUE_SEND( xHandle, xCoRoutineQueue, &xNumberToPost, NO_DELAY, &xResult ); | |
if( xResult != pdPASS ) | |
{ | |
// The message was not posted! | |
} | |
// Increment the number to be posted onto the queue. | |
xNumberToPost++; | |
// Delay for 100 ticks. | |
crDELAY( xHandle, 100 ); | |
} | |
// Co-routines must end with a call to crEND(). | |
crEND(); | |
}</pre> | |
* \defgroup crQUEUE_SEND crQUEUE_SEND | |
* \ingroup Tasks | |
*/ | |
#define crQUEUE_SEND( xHandle, pxQueue, pvItemToQueue, xTicksToWait, pxResult ) \ | |
{ \ | |
*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, xTicksToWait ); \ | |
if( *pxResult == errQUEUE_BLOCKED ) \ | |
{ \ | |
crSET_STATE0( xHandle ); \ | |
*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, 0 ); \ | |
} \ | |
if( *pxResult == errQUEUE_YIELD ) \ | |
{ \ | |
crSET_STATE1( xHandle ); \ | |
*pxResult = pdPASS; \ | |
} \ | |
} | |
/** | |
* croutine. h | |
* <pre> | |
crQUEUE_RECEIVE( | |
xCoRoutineHandle xHandle, | |
xQueueHandle pxQueue, | |
void *pvBuffer, | |
portTickType xTicksToWait, | |
portBASE_TYPE *pxResult | |
)</pre> | |
* | |
* The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine | |
* equivalent to the xQueueSend() and xQueueReceive() functions used by tasks. | |
* | |
* crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas | |
* xQueueSend() and xQueueReceive() can only be used from tasks. | |
* | |
* crQUEUE_RECEIVE can only be called from the co-routine function itself - not | |
* from within a function called by the co-routine function. This is because | |
* co-routines do not maintain their own stack. | |
* | |
* See the co-routine section of the WEB documentation for information on | |
* passing data between tasks and co-routines and between ISR's and | |
* co-routines. | |
* | |
* @param xHandle The handle of the calling co-routine. This is the xHandle | |
* parameter of the co-routine function. | |
* | |
* @param pxQueue The handle of the queue from which the data will be received. | |
* The handle is obtained as the return value when the queue is created using | |
* the xQueueCreate() API function. | |
* | |
* @param pvBuffer The buffer into which the received item is to be copied. | |
* The number of bytes of each queued item is specified when the queue is | |
* created. This number of bytes is copied into pvBuffer. | |
* | |
* @param xTickToDelay The number of ticks that the co-routine should block | |
* to wait for data to become available from the queue, should data not be | |
* available immediately. The actual amount of time this equates to is defined | |
* by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant | |
* portTICK_RATE_MS can be used to convert ticks to milliseconds (see the | |
* crQUEUE_SEND example). | |
* | |
* @param pxResult The variable pointed to by pxResult will be set to pdPASS if | |
* data was successfully retrieved from the queue, otherwise it will be set to | |
* an error code as defined within ProjDefs.h. | |
* | |
* Example usage: | |
<pre> | |
// A co-routine receives the number of an LED to flash from a queue. It | |
// blocks on the queue until the number is received. | |
static void prvCoRoutineFlashWorkTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
// Variables in co-routines must be declared static if they must maintain value across a blocking call. | |
static portBASE_TYPE xResult; | |
static unsigned portBASE_TYPE uxLEDToFlash; | |
// All co-routines must start with a call to crSTART(). | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// Wait for data to become available on the queue. | |
crQUEUE_RECEIVE( xHandle, xCoRoutineQueue, &uxLEDToFlash, portMAX_DELAY, &xResult ); | |
if( xResult == pdPASS ) | |
{ | |
// We received the LED to flash - flash it! | |
vParTestToggleLED( uxLEDToFlash ); | |
} | |
} | |
crEND(); | |
}</pre> | |
* \defgroup crQUEUE_RECEIVE crQUEUE_RECEIVE | |
* \ingroup Tasks | |
*/ | |
#define crQUEUE_RECEIVE( xHandle, pxQueue, pvBuffer, xTicksToWait, pxResult ) \ | |
{ \ | |
*pxResult = xQueueCRReceive( pxQueue, pvBuffer, xTicksToWait ); \ | |
if( *pxResult == errQUEUE_BLOCKED ) \ | |
{ \ | |
crSET_STATE0( xHandle ); \ | |
*pxResult = xQueueCRReceive( pxQueue, pvBuffer, 0 ); \ | |
} \ | |
if( *pxResult == errQUEUE_YIELD ) \ | |
{ \ | |
crSET_STATE1( xHandle ); \ | |
*pxResult = pdPASS; \ | |
} \ | |
} | |
/** | |
* croutine. h | |
* <pre> | |
crQUEUE_SEND_FROM_ISR( | |
xQueueHandle pxQueue, | |
void *pvItemToQueue, | |
portBASE_TYPE xCoRoutinePreviouslyWoken | |
)</pre> | |
* | |
* The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the | |
* co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR() | |
* functions used by tasks. | |
* | |
* crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to | |
* pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and | |
* xQueueReceiveFromISR() can only be used to pass data between a task and and | |
* ISR. | |
* | |
* crQUEUE_SEND_FROM_ISR can only be called from an ISR to send data to a queue | |
* that is being used from within a co-routine. | |
* | |
* See the co-routine section of the WEB documentation for information on | |
* passing data between tasks and co-routines and between ISR's and | |
* co-routines. | |
* | |
* @param xQueue The handle to the queue on which the item is to be posted. | |
* | |
* @param pvItemToQueue A pointer to the item that is to be placed on the | |
* queue. The size of the items the queue will hold was defined when the | |
* queue was created, so this many bytes will be copied from pvItemToQueue | |
* into the queue storage area. | |
* | |
* @param xCoRoutinePreviouslyWoken This is included so an ISR can post onto | |
* the same queue multiple times from a single interrupt. The first call | |
* should always pass in pdFALSE. Subsequent calls should pass in | |
* the value returned from the previous call. | |
* | |
* @return pdTRUE if a co-routine was woken by posting onto the queue. This is | |
* used by the ISR to determine if a context switch may be required following | |
* the ISR. | |
* | |
* Example usage: | |
<pre> | |
// A co-routine that blocks on a queue waiting for characters to be received. | |
static void vReceivingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
portCHAR cRxedChar; | |
portBASE_TYPE xResult; | |
// All co-routines must start with a call to crSTART(). | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// Wait for data to become available on the queue. This assumes the | |
// queue xCommsRxQueue has already been created! | |
crQUEUE_RECEIVE( xHandle, xCommsRxQueue, &uxLEDToFlash, portMAX_DELAY, &xResult ); | |
// Was a character received? | |
if( xResult == pdPASS ) | |
{ | |
// Process the character here. | |
} | |
} | |
// All co-routines must end with a call to crEND(). | |
crEND(); | |
} | |
// An ISR that uses a queue to send characters received on a serial port to | |
// a co-routine. | |
void vUART_ISR( void ) | |
{ | |
portCHAR cRxedChar; | |
portBASE_TYPE xCRWokenByPost = pdFALSE; | |
// We loop around reading characters until there are none left in the UART. | |
while( UART_RX_REG_NOT_EMPTY() ) | |
{ | |
// Obtain the character from the UART. | |
cRxedChar = UART_RX_REG; | |
// Post the character onto a queue. xCRWokenByPost will be pdFALSE | |
// the first time around the loop. If the post causes a co-routine | |
// to be woken (unblocked) then xCRWokenByPost will be set to pdTRUE. | |
// In this manner we can ensure that if more than one co-routine is | |
// blocked on the queue only one is woken by this ISR no matter how | |
// many characters are posted to the queue. | |
xCRWokenByPost = crQUEUE_SEND_FROM_ISR( xCommsRxQueue, &cRxedChar, xCRWokenByPost ); | |
} | |
}</pre> | |
* \defgroup crQUEUE_SEND_FROM_ISR crQUEUE_SEND_FROM_ISR | |
* \ingroup Tasks | |
*/ | |
#define crQUEUE_SEND_FROM_ISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) xQueueCRSendFromISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) | |
/** | |
* croutine. h | |
* <pre> | |
crQUEUE_SEND_FROM_ISR( | |
xQueueHandle pxQueue, | |
void *pvBuffer, | |
portBASE_TYPE * pxCoRoutineWoken | |
)</pre> | |
* | |
* The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the | |
* co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR() | |
* functions used by tasks. | |
* | |
* crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to | |
* pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and | |
* xQueueReceiveFromISR() can only be used to pass data between a task and and | |
* ISR. | |
* | |
* crQUEUE_RECEIVE_FROM_ISR can only be called from an ISR to receive data | |
* from a queue that is being used from within a co-routine (a co-routine | |
* posted to the queue). | |
* | |
* See the co-routine section of the WEB documentation for information on | |
* passing data between tasks and co-routines and between ISR's and | |
* co-routines. | |
* | |
* @param xQueue The handle to the queue on which the item is to be posted. | |
* | |
* @param pvBuffer A pointer to a buffer into which the received item will be | |
* placed. The size of the items the queue will hold was defined when the | |
* queue was created, so this many bytes will be copied from the queue into | |
* pvBuffer. | |
* | |
* @param pxCoRoutineWoken A co-routine may be blocked waiting for space to become | |
* available on the queue. If crQUEUE_RECEIVE_FROM_ISR causes such a | |
* co-routine to unblock *pxCoRoutineWoken will get set to pdTRUE, otherwise | |
* *pxCoRoutineWoken will remain unchanged. | |
* | |
* @return pdTRUE an item was successfully received from the queue, otherwise | |
* pdFALSE. | |
* | |
* Example usage: | |
<pre> | |
// A co-routine that posts a character to a queue then blocks for a fixed | |
// period. The character is incremented each time. | |
static void vSendingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex ) | |
{ | |
// cChar holds its value while this co-routine is blocked and must therefore | |
// be declared static. | |
static portCHAR cCharToTx = 'a'; | |
portBASE_TYPE xResult; | |
// All co-routines must start with a call to crSTART(). | |
crSTART( xHandle ); | |
for( ;; ) | |
{ | |
// Send the next character to the queue. | |
crQUEUE_SEND( xHandle, xCoRoutineQueue, &cCharToTx, NO_DELAY, &xResult ); | |
if( xResult == pdPASS ) | |
{ | |
// The character was successfully posted to the queue. | |
} | |
else | |
{ | |
// Could not post the character to the queue. | |
} | |
// Enable the UART Tx interrupt to cause an interrupt in this | |
// hypothetical UART. The interrupt will obtain the character | |
// from the queue and send it. | |
ENABLE_RX_INTERRUPT(); | |
// Increment to the next character then block for a fixed period. | |
// cCharToTx will maintain its value across the delay as it is | |
// declared static. | |
cCharToTx++; | |
if( cCharToTx > 'x' ) | |
{ | |
cCharToTx = 'a'; | |
} | |
crDELAY( 100 ); | |
} | |
// All co-routines must end with a call to crEND(). | |
crEND(); | |
} | |
// An ISR that uses a queue to receive characters to send on a UART. | |
void vUART_ISR( void ) | |
{ | |
portCHAR cCharToTx; | |
portBASE_TYPE xCRWokenByPost = pdFALSE; | |
while( UART_TX_REG_EMPTY() ) | |
{ | |
// Are there any characters in the queue waiting to be sent? | |
// xCRWokenByPost will automatically be set to pdTRUE if a co-routine | |
// is woken by the post - ensuring that only a single co-routine is | |
// woken no matter how many times we go around this loop. | |
if( crQUEUE_RECEIVE_FROM_ISR( pxQueue, &cCharToTx, &xCRWokenByPost ) ) | |
{ | |
SEND_CHARACTER( cCharToTx ); | |
} | |
} | |
}</pre> | |
* \defgroup crQUEUE_RECEIVE_FROM_ISR crQUEUE_RECEIVE_FROM_ISR | |
* \ingroup Tasks | |
*/ | |
#define crQUEUE_RECEIVE_FROM_ISR( pxQueue, pvBuffer, pxCoRoutineWoken ) xQueueCRReceiveFromISR( pxQueue, pvBuffer, pxCoRoutineWoken ) | |
/* | |
* This function is intended for internal use by the co-routine macros only. | |
* The macro nature of the co-routine implementation requires that the | |
* prototype appears here. The function should not be used by application | |
* writers. | |
* | |
* Removes the current co-routine from its ready list and places it in the | |
* appropriate delayed list. | |
*/ | |
void vCoRoutineAddToDelayedList( portTickType xTicksToDelay, xList *pxEventList ); | |
/* | |
* This function is intended for internal use by the queue implementation only. | |
* The function should not be used by application writers. | |
* | |
* Removes the highest priority co-routine from the event list and places it in | |
* the pending ready list. | |
*/ | |
signed portBASE_TYPE xCoRoutineRemoveFromEventList( const xList *pxEventList ); | |
#ifdef __cplusplus | |
} | |
#endif | |
#endif /* CO_ROUTINE_H */ |