crQUEUE_RECEIVE_FROM_ISR
[协程专用]

BaseType_t crQUEUE_SEND_FROM_ISR
                       (
                           QueueHandle_t xQueue,
                           void *pvBuffer,
                           BaseType_t * pxCoRoutineWoken
                       )

宏的 crQUEUE_SEND_FROM_ISR() 和 crQUEUE_RECEIVE_FROM_ISR() 是协程，相当于 任务使用的 xQueueSendFromISR() 和 xQueueReceiveFromISR() 函数 等效的协程。

crQUEUE_SEND_FROM_ISR() 和 crQUEUE_RECEIVE_FROM_ISR() 只能用于 在协程和 ISR 之间传递数据，而 xQueueSendFromISR() 和 xQueueReceiveFromISR() 只能用于 在任务和 ISR 之间 传递数据。

crQUEUE_RECEIVE_FROM_ISR 只能从 ISR 中调用，以从 协程中（发布到队列的协程）正在使用的队列接收数据 。

请参阅网络文档的协程部分， 了解有关在任务和协程之间以及在 ISR 和 协程之间传递数据的信息。

参数：

xQueue	队列的句柄，数据项将发布到此队列。
pvBuffer	指向缓冲区的指针，接收到的项目将被放入此缓冲区中。 创建队列时定义了队列将保留的项的大小，因此固定数量的字节将从队列复制到 pvBuffer。
pxCoRoutineWoken	协程在等待队列空间可用时可能会被阻塞。 如果 crQUEUE_RECEIVE_FROM_ISR 导致 协程解除阻塞，则 *pxCoRoutineWoken 将被设置为 pdTRUE ，否则 *pxCoRoutineWoken 将保持不变

返回：

如果从队列中成功接收到项目，则返回 pdTRUE，否则返回 pdFALSE。

 // 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( xQueue, &cCharToTx, &xCRWokenByPost ) )
         {
             SEND_CHARACTER( cCharToTx );
         }
     }
 }