USART — DMA 收发

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#include "gd32f30x.h"
#include <stdio.h>
#include "gd32f307c_eval.h"
#define ARRAYNUM(arr_name)     (uint32_t)(sizeof(arr_name) / sizeof(*(arr_name)))
#define USART0_DATA_ADDRESS    ((uint32_t)&USART_DATA(USART0))

int main(void)
{
    dma_parameter_struct dma_init_struct;
    /* enable DMA0 */
    rcu_periph_clock_enable(RCU_DMA0);
    /* initialize USART */
    gd_eval_com_init(EVAL_COM0);
    /* deinitialize DMA channel3(USART0 tx) */
    dma_deinit(DMA0, DMA_CH3);
    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 = ARRAYNUM(txbuffer);
    dma_init_struct.periph_addr = USART0_DATA_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(DMA0, DMA_CH3, &dma_init_struct);
    /* configure DMA mode */
    dma_circulation_disable(DMA0, DMA_CH3);   
    /* enable DMA channel3 */
    dma_channel_enable(DMA0, DMA_CH3);
    
    /* enable USART DMA for transmission */
    usart_dma_transmit_config(USART0, USART_TRANSMIT_DMA_ENABLE);

     /* wait DMA channel transfer complete */
    while(RESET == dma_flag_get(DMA0, DMA_CH3, DMA_INTF_FTFIF)){
    }

    while(1){
        /* deinitialize DMA channel4 (USART0 rx) */
        dma_deinit(DMA0, DMA_CH4);
        usart_flag_clear(USART0, USART_FLAG_RBNE);
        usart_dma_receive_config(USART0, USART_RECEIVE_DMA_ENABLE);
        dma_struct_para_init(&dma_init_struct);
        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 = 10;
        dma_init_struct.periph_addr = USART0_DATA_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(DMA0, DMA_CH4, &dma_init_struct);
        /* configure DMA mode */
        dma_circulation_disable(DMA0, DMA_CH4); 
        /* enable DMA channel4 */
        dma_channel_enable(DMA0, DMA_CH4);

        /* wait DMA channel transfer complete */
        while(RESET == dma_flag_get(DMA0, DMA_CH4, DMA_INTF_FTFIF)){
        }
        
        usart_dma_receive_config(USART0, USART_RECEIVE_DMA_DISABLE);
        printf("\n\r%s\n\r", rxbuffer);
    }
}