task - How to interrupt an xQueueReceive() API in FreeRTOS? -


in following code

  • sendmessage() api called user send message on usb
  • usbdatareceived() function called thread when data received on usb
  • task() thread created in init() reads queue filled sendmessage() , calls low level usb function send message
  • usbconnected() function called thread when usb device connected.

i need implement following behaviour:

  • once message has been sent, no new messages can sent when answer last message has arrived
  • when usbconnected() called, of queues must emptied , if thread task() waiting on queue answerqueue, has unblocked can go wait on queue commandqueue

an example of best solution listed below.

i had post event_queue_resetted message on both of queues particular order.

is possible achieve same result in less cumbersome way?

void usbhout(message_t ); int usbconnected; queuehandle_t messagequeue;    typedef enum {     event_queue_resetted,     event_new_message,     event_new_answer, } event_t;  typedef struct {     event_t event;     uint8_t data[32]; } commandqueue_t;  typedef struct {     event_t event;     uint8_t data[32]; } answerqueue_t;   void init(void) {   messagequeue = xqueuecreate(sizeof(message_t), 10);   answerqueue = xqueuecreate(sizeof(message_t), 10);   xtaskcreate(task, "", 200, null, 1, null); }  void usbconnected(void) {   commandevent.event = event_queue_resetted;   answerevent.event = event_queue_resetted;    usbconnected = 1;   xqueuereset(messagequeue);   xqueuereset(answerqueue);    /* order here fundmental */   xqueuesend(answerqueue, &answerevent, 0);   xqueuesend(messageqeueue, &commandevent, 0);  }   int sendmessage(uint8_t * data) {   commandqueue_t commandevent;    commandevent.event = event_new_message;   memcpy(&commandevent, message, 32);    if(xqueuesend(messagequeue, &commandevent, 0) == pdtrue)     return 0;   else     return -1; }   void usbdatareceived(uint8_t * data) {   answerqueue_t answerevent;   answerevent.event = event_new_answer;   memcpy(answerevent.data, data, 32);    xqueuesend(answerqueue, &answerevent,0); }   void task(void *pvparameters) {   commandqueue_t commandevent;   answerqueue_t answerevent;   commandcallback_t * callback;    while(1)   {      xqueuereceive(usbhstaticdata.commandsenderqueue, &commandevent, portmax_delay);       if(commandevent.event == commandsenderqueuedata_t::event_queue_resetted)      {        continue;      }       /* low level usb fucntion used send data */      usbdsenddata(command.data);       xqueuereceive(usbhstaticdata.answerreceivdqueue, &answerevent, portmax_delay);       if(answerevent.event == answerreceivedqueuedata_t::event_queue_resetted)      {          continue;      }      else if(answerevent.event == answerreceivedqueuedata_t::event_answer_received)      {        parsedata(answerevent.data);      }   }  }

you use queue sets freertos queue set api way create queue set containing queue , semaphore. task block on queue set. unblocked either receiving message queue or incrementing semaphore.


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