Hello, So I now have various tasks using a queue to send data, and a receive queue to send to the UART. It seems to work OK, but wants to hang up somewhere. It's a touch screen app - for example, the clock stops updating, and if I touch a "hot spot" on the screen that generates a message, all of a sudden the receive queue starts to respond and spew out all the messages that are apparently backed up. I have a queue size of 35. This is the receive function.

void QueueRxFunction( void *pvParameters ) { BaseTypet xStatus; QueueHandlet xQueue;

xQueue = (QueueHandle_t) pvParameters;

for(;;)
{
    //value of 1500 seems to work 
    xStatus = xQueueReceive( xQueue, &uartMssg, 1500 );                

    if( xStatus == pdPASS )
    {
        UBaseType_t spaces = uxQueueSpacesAvailable( xQueue );
        if( spaces == 1 )  assert(QUEUE_LOW_SPACE);
        uint8_t chkErr = SCRNCOM_GetResponse( uartMssg.message ); 
        if( chkErr != RCVD_PROMPT ) assert(UART_ERR1);
    }
    else
    {
        printf("Couldn't queue message: %s\n", uartMssg.message);
         assert(UART_ERR2);
    }

}

}

The function SCRNCOMGetResponse is basically a UART send and then poll for response: SCRNCOMGetResponse( char s) { while(s) { //while transmit buffer is not empty.... while( USARTGetFlagStatus(USART2, USARTFLAGTXE ) == RESET); USARTSendData(USART2, *s++); }

while(1) // poll response
{
    //wait for data: USART_FLAG_RXNE will be reset
    while( USART_GetFlagStatus( USART2, USART_FLAG_RXNE) == RESET ); 
    rxCode = USART_ReceiveData( USART2 ); 

    if( rxCode == RCVD_PROMPT )
    {
        //one more for 0xD (end of message)
        while( USART_GetFlagStatus( USART2, USART_FLAG_RXNE) == RESET ); 
        rxCode = USART_ReceiveData( USART2 );                         
        break;
    } 
}

return rxCode; }

If I reduce the value of xQueueReceive's wait to about 1200 or lower, I start to get the messaging printing and the assert handler going. With a UART baud of 115,200 it is hard to imagine the UART backing up and the receive queue having to wait 1-1/2 seconds. There's just not that many messages and formatting strings being sent out.

Every place I send to the queue, looks like this: xQueueSend(mssgQueue, (void*)&xMssg, portMAX_DELAY);

Should I be using a similar number of ticks to wait there too?

I also have the configCHECKFORSTACK_OVERFLOW defined, and the task to catch the error. It never lands there.

Thanks!

Have you tried using FreeRTOS+Trace to view how your application is running? I suspect it is getting 'stuck' somewhere you don't expect.