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diff --git a/freertos/include/croutine.h b/freertos/include/croutine.h new file mode 100644 index 0000000..4f003a0 --- /dev/null +++ b/freertos/include/croutine.h @@ -0,0 +1,762 @@ +/* + FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd. + All rights reserved + + VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. + + 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 modification 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. Full license text is available on the following + link: http://www.freertos.org/a00114.html + + *************************************************************************** + * * + * FreeRTOS provides completely free yet professionally developed, * + * robust, strictly quality controlled, supported, and cross * + * platform software that is more than just the market leader, it * + * is the industry's de facto standard. * + * * + * Help yourself get started quickly while simultaneously helping * + * to support the FreeRTOS project by purchasing a FreeRTOS * + * tutorial book, reference manual, or both: * + * http://www.FreeRTOS.org/Documentation * + * * + *************************************************************************** + + http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading + the FAQ page "My application does not run, what could be wrong?". Have you + defined configASSERT()? + + http://www.FreeRTOS.org/support - In return for receiving this top quality + embedded software for free we request you assist our global community by + participating in the support forum. + + http://www.FreeRTOS.org/training - Investing in training allows your team to + be as productive as possible as early as possible. Now you can receive + FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers + Ltd, and the world's leading authority on the world's leading RTOS. + + http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, + including FreeRTOS+Trace - an indispensable productivity tool, a DOS + compatible FAT file system, and our tiny thread aware UDP/IP stack. + + http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate. + Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS. + + http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High + Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS + licenses offer ticketed support, indemnification and commercial middleware. + + http://www.SafeRTOS.com - High Integrity Systems also provide a safety + engineered and independently SIL3 certified version for use in safety and + mission critical applications that require provable dependability. + + 1 tab == 4 spaces! +*/ + +#ifndef CO_ROUTINE_H +#define CO_ROUTINE_H + +#ifndef INC_FREERTOS_H + #error "include FreeRTOS.h must appear in source files before include croutine.h" +#endif + +#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 * CoRoutineHandle_t; + +/* Defines the prototype to which co-routine functions must conform. */ +typedef void (*crCOROUTINE_CODE)( CoRoutineHandle_t, UBaseType_t ); + +typedef struct corCoRoutineControlBlock +{ + crCOROUTINE_CODE pxCoRoutineFunction; + ListItem_t xGenericListItem; /*< List item used to place the CRCB in ready and blocked queues. */ + ListItem_t xEventListItem; /*< List item used to place the CRCB in event lists. */ + UBaseType_t uxPriority; /*< The priority of the co-routine in relation to other co-routines. */ + UBaseType_t uxIndex; /*< Used to distinguish between co-routines when multiple co-routines use the same co-routine function. */ + uint16_t uxState; /*< Used internally by the co-routine implementation. */ +} CRCB_t; /* Co-routine control block. Note must be identical in size down to uxPriority with TCB_t. */ + +/** + * croutine. h + *<pre> + BaseType_t xCoRoutineCreate( + crCOROUTINE_CODE pxCoRoutineCode, + UBaseType_t uxPriority, + UBaseType_t 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( CoRoutineHandle_t xHandle, UBaseType_t 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 TickType_t uxFlashRates[ 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 int32_t 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 ) + { + uint8_t ucParameterToPass; + TaskHandle_t 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 + */ +BaseType_t xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, UBaseType_t uxPriority, UBaseType_t 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( CoRoutineHandle_t 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( CoRoutineHandle_t xHandle, UBaseType_t uxIndex ) + { + // Variables in co-routines must be declared static if they must maintain value across a blocking call. + static int32_t 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( ( ( CRCB_t * )( 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( CoRoutineHandle_t xHandle, UBaseType_t uxIndex ) + { + // Variables in co-routines must be declared static if they must maintain value across a blocking call. + static int32_t 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 ) ( ( CRCB_t * )( xHandle ) )->uxState = (__LINE__ * 2); return; case (__LINE__ * 2): +#define crSET_STATE1( xHandle ) ( ( CRCB_t * )( xHandle ) )->uxState = ((__LINE__ * 2)+1); return; case ((__LINE__ * 2)+1): + +/** + * croutine. h + *<pre> + crDELAY( CoRoutineHandle_t xHandle, TickType_t 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_PERIOD_MS + * can be used to convert ticks to milliseconds. + * + * Example usage: + <pre> + // Co-routine to be created. + void vACoRoutine( CoRoutineHandle_t xHandle, UBaseType_t 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_PERIOD_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( + CoRoutineHandle_t xHandle, + QueueHandle_t pxQueue, + void *pvItemToQueue, + TickType_t xTicksToWait, + BaseType_t *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_PERIOD_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( CoRoutineHandle_t xHandle, UBaseType_t uxIndex ) + { + // Variables in co-routines must be declared static if they must maintain value across a blocking call. + static BaseType_t xNumberToPost = 0; + static BaseType_t 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( + CoRoutineHandle_t xHandle, + QueueHandle_t pxQueue, + void *pvBuffer, + TickType_t xTicksToWait, + BaseType_t *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_PERIOD_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( CoRoutineHandle_t xHandle, UBaseType_t uxIndex ) + { + // Variables in co-routines must be declared static if they must maintain value across a blocking call. + static BaseType_t xResult; + static UBaseType_t 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( + QueueHandle_t pxQueue, + void *pvItemToQueue, + BaseType_t 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( CoRoutineHandle_t xHandle, UBaseType_t uxIndex ) + { + char cRxedChar; + BaseType_t 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 ) + { + char cRxedChar; + BaseType_t 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( + QueueHandle_t pxQueue, + void *pvBuffer, + BaseType_t * 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( CoRoutineHandle_t xHandle, UBaseType_t uxIndex ) + { + // cChar holds its value while this co-routine is blocked and must therefore + // be declared static. + static char cCharToTx = 'a'; + BaseType_t 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 ) + { + char cCharToTx; + BaseType_t 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( TickType_t xTicksToDelay, List_t *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. + */ +BaseType_t xCoRoutineRemoveFromEventList( const List_t *pxEventList ); + +#ifdef __cplusplus +} +#endif + +#endif /* CO_ROUTINE_H */ |