C-在双缓冲区交换期间处理UART ISR

Question

我正在为sTM32F处理器上的UART进行双重缓冲区。下面的示例每次运行UART ISR时，将数据添加到缓冲区中。然后，当主要进程要从中取出数据时，此缓冲区随后交换。

我担心可能的转角状况。我交换缓冲区后，ISR可能会发射，但在重置接收缓冲区计数之前。这意味着我的缓冲尺寸和计数将不超出同步。

处理此角案的最佳方法是什么？

uint8_t rxBufferA[MAX_RX_BUFFER_SIZE];
uint8_t rxBufferB[MAX_RX_BUFFER_SIZE];
uint8_t *receivingBuffer;
uint8_t *processingBuffer;
volatile uint32_t rxBufferSize;
uart_isr() {
  receivingBuffer[rxBufferSize++] = RECEIVE_DATA_REGISTER
}

main() {
  receivingBuffer = &rxBufferA;
  processingBuffer = &rxBufferB;
  while(1) {
    if (rxBufferSize > 0) {
      uint32_t i = 0;
      uint8_t *ptemp = receivingBuffer;
      uint8_t bufferSize = 0;
      /* zero out processing buffer */
      memset(processingBuffer, 0, MAX_RX_BUFFER_SIZE);
      /* swap receiving and processing buffers */
      receivingBuffer = processingBuffer
      processingBuffer = ptemp;
      /* WHAT IF THE ISR FIRES HERE??? */         
      /* save off buffer size and reset count */
      bufferSize = rxBufferSize;
      rxBufferSize = 0;
      /* process rx data */
    } 
  }
}

Answer 1

您需要关键部分。交换缓冲区时禁用用户中断。

不需要btw零