GD32E230串口DMA发送接收

串口使用DMA可以节省MCU运行的时间，节省效率，把单片机内部资源用到最优化。串口DMA就是配置好初始化后，调用串口发送程序时先把要发送的数据保存到DMA缓存，然后使能DMA发送，接下来串口就由硬件自动发送数据，软件可以继续处理其他功能。
串口初始化分一下几个阶段：
·GPIO初始化
·串口初始化
·中断使能初始化
·DMA初始化

void Uart_Init(void){/* initilize the com */    com_gpio_init();    com_usart_init();    /*configure DMA interrupt*/    nvic_config();  TxRx_DMA_Config();}

void com_gpio_init(void) //以串口0为例，gpio为PA9 PA10{rcu_periph_clock_enable(RCU_GPIOA);//使能IO口时钟gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_9);//配置复用功能gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_10);/* configure USART Tx as alternate function push-pull */    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_9);    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_9);   /* configure USART Rx as alternate function push-pull */    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_10);    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_10);}

void com_usart_init(void)//串口初始化{/* enable USART clock */    rcu_periph_clock_enable(RCU_USART0);//使能串口时钟    /* USART configure */    usart_deinit(USART0);    usart_baudrate_set(USART0, 115200U);    usart_receive_config(USART0, USART_RECEIVE_ENABLE);    usart_transmit_config(USART0, USART_TRANSMIT_ENABLE);    usart_enable(USART0);}

void nvic_config(void)
{
nvic_irq_enable(DMA_Channel1_2_IRQn, 0);
}

void TxRx_DMA_Config(void)//DMA发送接收初始化{dma_parameter_struct dma_init_struct;    /* enable DMA clock */    rcu_periph_clock_enable(RCU_DMA); /* initialize DMA channel1 */    dma_deinit(DMA_CH1);    dma_struct_para_init(&dma_init_struct);    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 = TX_BUF_LEN;    dma_init_struct.periph_addr = USART0_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_CH1, &dma_init_struct);    /* initialize DMA channel2 */    dma_deinit(DMA_CH2);    dma_init_struct.direction = DMA_PERIPHERAL_TO_MEMORY;    dma_init_struct.memory_addr = (uint32_t)rxbuffer;    dma_init_struct.memory_inc = DMA_MEMORY_INCREASE_ENABLE;    dma_init_struct.memory_width = DMA_MEMORY_WIDTH_8BIT;    dma_init_struct.number = RX_BUF_LEN;    dma_init_struct.periph_addr = USART0_RDATA_ADDRESS;    dma_init_struct.periph_inc = DMA_PERIPH_INCREASE_DISABLE;    dma_init_struct.memory_width = DMA_PERIPHERAL_WIDTH_8BIT;    dma_init_struct.priority = DMA_PRIORITY_ULTRA_HIGH;    dma_init(DMA_CH2, &dma_init_struct);    /* configure DMA mode */    dma_circulation_disable(DMA_CH1);    dma_memory_to_memory_disable(DMA_CH1);    dma_circulation_disable(DMA_CH2);    dma_memory_to_memory_disable(DMA_CH2);    /* USART DMA enable for reception */    usart_dma_receive_config(USART0, USART_DENR_ENABLE);    /* enable DMA channel2 transfer complete interrupt */    dma_interrupt_enable(DMA_CH2, DMA_INT_FTF);    /* enable DMA channel2 */    dma_channel_enable(DMA_CH2);    /* USART DMA enable for transmission */    usart_dma_transmit_config(USART0, USART_DENT_ENABLE);    /* enable DMA channel1 transfer complete interrupt */    dma_interrupt_enable(DMA_CH1, DMA_INT_FTF);    /* enable DMA channel1 */    dma_channel_enable(DMA_CH1);}```cvoid Use_DMA_SendTX1_Data(uint8_t *buffter, uint8_t writeLen){//串口DMA发送函数，发送数据时调用这个函数，发送完成后会产生一个中断uint8 i;//, Tx_Buf1[64]; dma_parameter_struct dma_init_struct; for (i = 0; i < writeLen; i ++) {  txbuffer[i] = buffter[i]; } dma_channel_disable(DMA_CH1); dma_memory_address_config(DMA_CH1, (uint32)txbuffer);  dma_transfer_number_config(DMA_CH1, (uint32_t)writeLen); /* enable DMA channel1 */  dma_channel_enable(DMA_CH1); /* USART DMA enable for transmission */  usart_dma_transmit_config(USART0, USART_DENT_ENABLE);}

void DMA_Channel1_2_IRQHandler(void)//发送接收通道中断处理{static uint32 Rx_num;    if(RESET != dma_interrupt_flag_get(DMA_CH1, DMA_INT_FLAG_FTF)){        dma_interrupt_flag_clear(DMA_CH1, DMA_INT_FLAG_G);    }    if(RESET != dma_interrupt_flag_get(DMA_CH2, DMA_INT_FLAG_FTF)){    dma_channel_disable(DMA_CH2);        dma_interrupt_flag_clear(DMA_CH2, DMA_INT_FLAG_G);    dma_flag_clear(DMA_CH2, DMA_FLAG_G);    Rx_num = dma_transfer_number_get(DMA_CH2);    dma_transfer_number_config(DMA_CH2,RX_BUF_LEN);    dma_channel_enable(DMA_CH2);    }}

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