串口发送+DMA的使用Demo

Gavin

void com_usart_init(void)
{
    /* enable USART clock */
    rcu_periph_clock_enable(RCU_USART1);

    /* enable COM GPIO clock */
    rcu_periph_clock_enable(RCU_GPIOA);

    /* connect port to USART TX */
    gpio_af_set(GPIOA, GPIO_AF_7, GPIO_PIN_2);

    /* connect port to USART RX */
    gpio_af_set(GPIOA, GPIO_AF_7, GPIO_PIN_3);

    /* configure USART TX as alternate function push-pull */
    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_2);
    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_2);

    /* configure USART RX as alternate function push-pull */
    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_3);
    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_3);

    /* USART configure */
    usart_deinit(USART1);
    usart_baudrate_set(USART1, 115200U);
    usart_receive_config(USART1, USART_RECEIVE_ENABLE);
    usart_transmit_config(USART1, USART_TRANSMIT_ENABLE);

    usart_enable(USART1);
}
    dma_parameter_struct dma_init_struct;
    /* enable DMA clock */
    rcu_periph_clock_enable(RCU_DMA);
    /* initialize the com */
    com_usart_init();
    /*configure DMA interrupt*/
    nvic_config();

void Dma_Init(void)
{
    /* initialize DMA channel 0 */
    dma_deinit(DMA_CH0);
    dma_struct_para_init(&dma_init_struct);
    dma_init_struct.request      = DMA_REQUEST_USART1_TX;
    dma_init_struct.direction    = DMA_MEMORY_TO_PERIPHERAL;
    dma_init_struct.memory_addr  = (uint32_t)txbuffer;
    dma_init_struct.memory_inc   = DMA_MEMORY_INCREASE_ENABLE;
    dma_init_struct.memory_width = DMA_MEMORY_WIDTH_8BIT;
    dma_init_struct.number       = ARRAYNUM(txbuffer);
    dma_init_struct.periph_addr  = (uint32_t)USART1_TDATA_ADDRESS;
    dma_init_struct.periph_inc   = DMA_PERIPH_INCREASE_DISABLE;
    dma_init_struct.periph_width = DMA_PERIPHERAL_WIDTH_8BIT;
    dma_init_struct.priority     = DMA_PRIORITY_ULTRA_HIGH;
    dma_init(DMA_CH0, &dma_init_struct);

    /* configure DMA mode */
//这里要使用循环模式，不然DMA只会触发一次
    dma_circulation_enable(DMA_CH0);
    dma_memory_to_memory_disable(DMA_CH0);
    /* disable the DMAMUX_MUXCH0 synchronization mode */
    dmamux_synchronization_disable(DMAMUX_MUXCH0);
    /* USART DMA enable for transmission */
    usart_dma_transmit_config(USART1, USART_TRANSMIT_DMA_ENABLE);
    /* enable DMA channel 0 transfer complete interrupt */
    dma_interrupt_enable(DMA_CH0, DMA_INT_FTF);
    /* enable DMA channel 0 */
    dma_channel_enable(DMA_CH0);
}

void uart_dma_send(uint8_t *buf, uint16_t len,dma_channel_enum channelx)
{
//关闭DMA_EN
    dma_channel_disable(DMA_CH0);
    usart_dma_transmit_config(USART1, USART_TRANSMIT_DMA_DISABLE);
//更改DMA传送字节数
    DMA_CHCNT(channelx) = len;
//更改DMA的存储地址
     DMA_CHMADDR(channelx) = (uint32_t)buf;

        usart_dma_transmit_config(USART1, USART_TRANSMIT_DMA_ENABLE);
    dma_channel_enable(DMA_CH0);
}