main代码：while (1) { / First transmit data, then start DMA receive / if (loop_TX < 0xFF) { loop_TX++; HAL_UART_Transmit(&huart2, &loop_TX, 1, 100); HAL_Delay(100); / Start DMA receive with IDLE detection / HAL_UARTEx_ReceiveToIdle_DMA(&huart2, &loop_RX, 1); / Wait for DMA transfer to complete / HAL_Delay(100); / Flush cache to ensure DMA data is visible to CPU / SCB_InvalidateDCache_by_Addr(&loop_RX, sizeof(loop_RX)); printf("[MAIN] TX: %02X, RX: %02X\r\n", loop_TX, loop_RX); } } void GPDMA1_Channel0_IRQHandler(void) { / USER CODE BEGIN GPDMA1_Channel0_IRQn 0 / printf("[GPDMA1_Channel0] DMA done, CNDTR=%u, CSAR=0x%08lX, CDAR=0x%08lX, CTR1=0x%08lX\r\n", __HAL_DMA_GET_COUNTER(&handle_GPDMA1_Channel0), handle_GPDMA1_Channel0.Instance->CSAR, handle_GPDMA1_Channel0.Instance->CDAR, handle_GPDMA1_Channel0.Instance->CTR1); / USER CODE END GPDMA1_Channel0_IRQn 0 / HAL_DMA_IRQHandler(&handle_GPDMA1_Channel0); / USER CODE BEGIN GPDMA1_Channel0_IRQn 1 /

/ USER CODE END GPDMA1_Channel0_IRQn 1 / } void USART2_IRQHandler(void) { / USER CODE BEGIN USART2_IRQn 0 / if (__HAL_UART_GET_FLAG(&huart2, UART_FLAG_IDLE)) {

__HAL_UART_CLEAR_IDLEFLAG(&huart2);

uint16_t dma_cntr = __HAL_DMA_GET_COUNTER(huart2.hdmarx);

/ Flush cache to ensure DMA data is visible to CPU / SCB_InvalidateDCache_by_Addr(&loop_RX, sizeof(loop_RX));

printf("[USART2] IDLE, DMA CNDTR=%u, RX=%02X, RDR=%02X\r\n", dma_cntr, loop_RX, huart2.Instance->RDR); } / USER CODE END USART2_IRQn 0 / HAL_UART_IRQHandler(&huart2); / USER CODE BEGIN USART2_IRQn 1 / / USER CODE END USART2_IRQn 1 / } 打印信息看DMA中断进去了，IDLE中断进去了，ROR是正确的，loop_RX却维持初始化的值。 [MAIN] loop_RX addr=0x20000029[GPDMA1_Channel0] DMA done, CNDTR=0, CSAR=0x40004424, CDAR=0x20000029, CTR1=0x00000000[MAIN] TX: B4, RX: 0F[USART2] IDLE, DMA CNDTR=0, RX=0F, RDR=B5[MAIN] loop_RX addr=0x20000029[GPDMA1_Channel0] DMA done, CNDTR=0, CSAR=0x40004424, CDAR=0x20000029, CTR1=0x00000000[MAIN] TX: B5, RX: 0F[USART2] IDLE, DMA CNDTR=0, RX=0F, RDR=B6[MAIN] loop_RX addr=0x20000029[GPDMA1_Channel0] DMA done, CNDTR=0, CSAR=0x40004424, CDAR=0x20000029, CTR1=0x00000000

USART2 TX直接接在了RX上。