USART错误中断所有时间问题

对不起忘了附加开始代码



      以下为原文

    Sorry forgot to attach the start code
void SendMessage(int length){
   SYS_PORTS_PinSet(PORTS_ID_0, PORT_CHANNEL_D, PORTS_BIT_POS_6); //change RS485 to transmitt mode
   remainingdatalength = length; //set message length for isr
   PLIB_INT_VectorPrioritySet(INT_ID_0, INT_VECTOR_UART2_TX, INT_PRIORITY_LEVEL3); //enables interrupts, triggers interrupt
}

是的，我也看到了。每当出现框架错误时，我使用Orthier-ISRS（动态USAT模型）进行相同的锁定。现在我使用静态实现，因为在协调中没有9位的支持（见注释）：看来，直到接收寄存器（ReaRead）（Read Read）之前，错误也不会被清除。在中断处理程序之外，这意味着你会被锁定在错误ISR中——一旦退出，它就重新进入。为了处理这个问题，接收ISR还需要清除任何错误：使用这个，我可以说它现在处理用于锁定它的框架错误。



      以下为原文

    Yes, I have seen this too. I experienced the same lock-up using Harmony ISRs (dynamic USART model) whenever a framing error occurred.
 
I now use a static implementation because there was no 9-bit support in Harmony (see comment for experience):
 
/* Called from an Err ISR */
/* WARNING! Despite the documentation, reading a parity or framing error does
 * NOT clear the interrupt and we get stuck in the FAULT int if enabled.
 * If you enable the interrupt, stress-test at a low baud rate. */
void SerialErrISR(SERIAL_PORT *this)
{
 /* Speed check for no errors - normal state */
 if (USART_ERROR_NONE == PLIB_USART_ErrorsGet(this->PhysicalUsartID))
  return;

 /* Handle errors */

 /* Although this is meant to cause an interrupt, it appears not to... */
 if (PLIB_USART_ReceiverOverrunHasOccurred(this->PhysicalUsartID))
 {
  PLIB_USART_ReceiverOverrunErrorClear(this->PhysicalUsartID);
  this->SerErrors |= SER_RX_OVERRUN;
 }

 /* Although reading this is meant to clear the interrupt, it appears not
  * to... */
 if (PLIB_USART_ReceiverFramingErrorHasOccurred(this->PhysicalUsartID))
 {
  this->SerErrors |= SER_RX_FRAMING;
 }
 /* Although reading this is meant to clear the interrupt, it appears not
  * to... */
 if (PLIB_USART_ReceiverParityErrorHasOccurred(this->PhysicalUsartID))
 {
  this->SerErrors |= SER_RX_PARITY;
 }
}
 
It appears that the error won't get cleared until the receive register is (also) read. Outside an interrupt handler, this means you get locked up in the Error ISR - as soon as it exits it re-enters. To deal with this, the Receive ISR needs to clear any errors as well:
 

/* Called from an Rx ISR */
void SerialRxISR(SERIAL_PORT *this)
{
    /* Check and clear any faults. Note that enabling the FAULT interrupt is
     * fatal for framing errors since reading the fault does not clear it, despite
     * the documentation. Also, for the overrun error, no interrupt occurs. */
    this->SerialErrISR();
    /* Only attempt to receive if we've got data */
    if (PLIB_USART_ReceiverDataIsAvailable(this->PhysicalUsartID))
    {
        /* If there is a callback for start of Rx, call it now */
        if (this->RxStarts)
            this->RxStarts();
        if (this->DataBits == EIGHT_DATA_BITS) /* 8-bit data */
       {
           BYTE Data = PLIB_USART_ReceiverByteReceive(this->PhysicalUsartID);
           if (!AddToCircBuf(this->serRxBuffer, SERIAL_RX_BUFFER_SIZE, &Data, 1, &this->serRxWrPtr, &this->serRxRdPtr))
                this->SerErrors |= SER_RX_OVERRUN;
        }
       else /* 9-bit data */
       {
           WORD Data = PLIB_USART_Receiver9BitsReceive(this->PhysicalUsartID);
           if (!AddToCircBuf(this->serRxBuffer, SERIAL_RX_BUFFER_SIZE, (BYTE*)&Data, 2, &this->serRxWrPtr, &this->serRxRdPtr))
               this->SerErrors |= SER_RX_OVERRUN;
       }
    }
    else
    {
        this->SerErrors |= SER_RX_UNDERRUN;
    }
    /* If there is no data pending despite the interrupt, signal an RxEnd */
    if (this->IsSerialRxBufferEmpty())
        ;
}

 
Using this I can say that it now handles framing errors that used to lock it up.