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下面的 IRQ 处理程序耗尽了 USART3 传入的 32 个字节数据。第一个 IRQ TC 事件读取前 6 个字节,然后重新编程 DMA 引擎以读取最后 24 个字节。第二个 TC 重新绘制它以再次读取标头此方法将允许使用 DMA 的可变长度消息。但是我似乎无法更改 DMA 起始地址。我希望能够将每条消息存储在单独的缓冲区中,但是它只是在收到每条消息时将第一个缓冲区覆盖。我究竟做错了什么?微控制器是 STM32F103ze (Cortex-M3)。

void DMA1_Channel3_IRQHandler(void)
{
    uint32_t tmpreg = 0;
     /* Test on DMA1 Channel3 Transfer Complete interrupt */
     if(DMA_GetITStatus(DMA1_IT_TC3)) 
     {
          if (rx3_dma_state == RECIEVE_HEADER )
          {
               DMA_Cmd(DMA1_Channel3, DISABLE);/* Disable DMA1_Channel2 transfer*/
               // Now that have received the header. Configure the DMA engine to receive
               // the data portion of the message
               DMA_SetCurrDataCounter(DMA1_Channel3,26);
               DMA_Cmd(DMA1_Channel3, ENABLE);
          } else if ( rx3_dma_state == RECIEVE_MSG )
          {
               //CurrDataCounterEnd3 = DMA_GetCurrDataCounter(DMA1_Channel3);
               DMA_Cmd(DMA1_Channel3, DISABLE);
               /* Get Current Data Counter value after complete transfer */
               USART3_Rx_DMA_Channel_Struct->CMAR = (uint32_t) RxBuffer3LookUp[rx_buffer_index];
               DMA_SetCurrDataCounter(DMA1_Channel3, 6);
               DMA_Cmd(DMA1_Channel3,ENABLE);
               // Set up DMA to write into the next buffer slot (1 of 8)
               ++rx_buffer_index;
               rx_buffer_index %= 8;
          }
          /* Clear DMA1 Channel6 Half Transfer, Transfer Complete and Global interrupt pending bits */
          DMA_ClearITPendingBit(DMA1_IT_GL3);
     }      
     // Update the state to read fake header of 6 bytes
     // or to read the fake data section of the message 26 bytes
     ++rx3_dma_state;
     rx3_dma_state %= 2;
     isr_sem_send(dma_usart3_rx_sem);
}
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1 回答 1

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你说:

...重新编程 DMA 引擎以读取最后 24 个字节。

但你的代码说:

DMA_SetCurrDataCounter(DMA1_Channel3,26);

那正确吗?是24还是26?

于 2011-10-19T12:31:55.830 回答