而且DMA的时钟在使能之后不能立即操作,要等个一会儿.不然DMA发送也不能正常工作.

越来越欢乐了.

是我错怪051K8了.刚才串口接线RX端口掉下来了.线没接好自然无法使用.

下面贴程序了.

unsigned char g_o_buf_0[UART1_O_BUF_SIZE];

void Uart::init_UART1(void){
    SET_BIT(RCC->APB2ENR,RCC_APB2ENR_USART1EN);
    SET_BIT(RCC->AHBENR,RCC_AHBENR_GPIOAEN);
    GPIOA->AFR[1]|=(1<<4)|(1<<8);
    GPIOA->PUPDR|=GPIO_PUPDR_PUPDR9_0|GPIO_PUPDR_PUPDR10_0;
    GPIOA->OSPEEDR|=GPIO_OSPEEDR_OSPEEDR9|GPIO_OSPEEDR_OSPEEDR10;
    GPIOA->MODER|=GPIO_MODER_MODER9_1|GPIO_MODER_MODER10_1;
    USART1->BRR=F_CPU/UART1_BAUDRATE;
    NVIC_EnableIRQ(USART1_IRQn);
    SET_BIT(USART1->CR1,USART_CR1_RE|USART_CR1_TE|USART_CR1_RXNEIE|USART_CR1_UE);
    Dma::config(DMA1_Channel2,(unsigned long)&USART1->TDR,(unsigned long)g_o_buf_0);
}


extern "C"{
    void DMA1_Channel2_3_IRQHandler(void){
        while(CHK_BIT(USART1->ISR,USART_ISR_TC));
        SET_BIT(DMA1->IFCR,DMA_IFCR_CGIF2);
        CLR_BIT(DMA1_Channel2->CCR,DMA_CCR_EN);
        CLR_BIT(USART1->CR3,USART_CR3_DMAT);
    }
}


void Dma::config(
    DMA_Channel_TypeDef *dma_chx,
    unsigned long periphera_address,
    unsigned long memory_address
){
        SET_BIT(RCC->AHBENR,RCC_AHBENR_DMAEN);
    Timer::delay_stuck(1000);
        dma_chx->CPAR=periphera_address;    //DMA1 ÍâÉèµØÖ·
        dma_chx->CMAR=memory_address;       //DMA1,´æ´¢Æ÷µØÖ·
        SET_REG(dma_chx->CCR,DMA_CCR_PL_0|DMA_CCR_MINC|DMA_CCR_DIR|DMA_CCR_TCIE);
    SET_BIT(DMA1->IFCR,DMA_IFCR_CGIF2);
    NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
}

void Dma::enable(DMA_Channel_TypeDef *dma_chx,unsigned short size){
        dma_chx->CNDTR=size;                //DMA1,´«ÊäÊý¾ÝÁ¿
    SET_REG(USART1->CR3,USART_CR3_DMAT);
    SET_BIT(dma_chx->CCR,DMA_CCR_EN);
}

还是有问题,在接收与发送之间来回转换几次,DMA会有几次中断不进去.