Question

我正在STM32F处理器上为UART使用双缓冲区。每次UART ISR运行时，以下示例将数据添加到缓冲区。然后，当主进程要从中提取数据时，将交换此缓冲区。

我担心可能出现的转弯情况。在交换缓冲区之后但在重置接收缓冲区计数之前，ISR可能会触发。这意味着我的缓冲区大小和计数将不同步。

处理这种极端情况的最佳方法是什么？

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调零

在双缓冲区交换期间处理UART ISR

1 个答案: