AVRFreaks.net

static void usart_int_handler(void)
{
   int c = 0;
    if(USART->csr & AVR32_USART_CSR_RXRDY_MASK)
   {
        usart_read_char(USART, &c);
        if ((char)c == BS)
        {
            if(usart_rx_idx > 0) usart_rx_idx--;
            print(USART, CUB1 CLEARLCR);
        }
        else if ((char)c == CR)
        {
         //When CR is detected without any input, refresh screen
         if (usart_rx_idx == 0)
         {
            work_reg |= USART_RX_NOIN;
         }
         else
         {
            //Set bit 1 for DataRDY
            work_reg |= USART_RX_DRDY;
            // Reset RX Index
            usart_rx_idx = 0;
         }         
        }
        else
        {
            usart_rx_buffer[usart_rx_idx++] = (char)c;
            usart_write_char(USART, c); // echo
        }       
    }   
}

static portBASE_TYPE prvUSART_ISR_NonNakedBehaviour( void )
{
   /* Now we can declare the local variables. */
   signed portCHAR     cChar;
   portBASE_TYPE     xHigherPriorityTaskWoken = pdFALSE;
   unsigned portLONG     ulStatus;
   volatile avr32_usart_t  *usart = serialPORT_USART;
   portBASE_TYPE retstatus;

   /* What caused the interrupt? */
   ulStatus = usart->csr & usart->imr;

   if (ulStatus & AVR32_USART_CSR_TXRDY_MASK)
   {
      /* The interrupt was caused by the THR becoming empty.  Are there any
      more characters to transmit?
      Because FreeRTOS is not supposed to run with nested interrupts, put all OS
      calls in a critical section . */
      portENTER_CRITICAL();
         retstatus = xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken );
      portEXIT_CRITICAL();

      if (retstatus == pdTRUE)
      {
         /* A character was retrieved from the queue so can be sent to the
          THR now. */
         usart->thr = cChar;
         
      }
      else
      {
         /* Queue empty, nothing to send so turn off the Tx interrupt. */
         usart->idr = AVR32_USART_IDR_TXRDY_MASK;
      }
   }

   if (ulStatus & AVR32_USART_CSR_RXRDY_MASK)
   {
      /* The interrupt was caused by the receiver getting data. */
      cChar = usart->rhr; //TODO

      /* Because FreeRTOS is not supposed to run with nested interrupts, put all OS
      calls in a critical section . */
      portENTER_CRITICAL();
         //Upon recieving a serialDELIMITER character, wake the Terminal Up
         if (cChar == serialDELIMITER)
         {
            xTaskResumeFromISR(menuTermHandle);
         }
         // Is char a backspace?
         else if(cChar == BS)
         {
            // pop off last char, but don't do anything with it
            xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken);
            //Send out cursor move left one?
         }
         else
         {
            xQueueSendFromISR(xRxedChars, &cChar, &xHigherPriorityTaskWoken);
            // Echo Char
            #if configSERIAL_ECHO
            usart->thr = cChar;
            #endif
         }
         
      portEXIT_CRITICAL();
   }

   /* The return value will be used by portEXIT_SWITCHING_ISR() to know if it
   should perform a vTaskSwitchContext(). */
   return ( xHigherPriorityTaskWoken );
}

#define CUB1 "\x1B[1D"   //!< Move Curser to the Left 1 Col