先查看用户手册，找到USART外设对应的DMA通道
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#define BUF_LEN 64U uint8_t g_dma_rx_finish; char g_dma_rx_buf[BUF_LEN]; //用于DMA数据接收 char g_dma_tx_buf[BUF_LEN]; //用于DMA数据发送 char g_uart0_rx_buf[BUF_LEN]; //DMA数据接收完成，及时拷贝出去，在中断外部处理数据 void uart0_dma_init(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)g_dma_tx_buf; dma_init_struct.memory_inc = DMA_MEMORY_INCREASE_ENABLE; dma_init_struct.memory_width = DMA_MEMORY_WIDTH_8BIT; dma_init_struct.number = BUF_LEN; dma_init_struct.periph_addr = USART_TDATA(USART0); 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)g_dma_rx_buf; dma_init_struct.memory_inc = DMA_MEMORY_INCREASE_ENABLE; dma_init_struct.memory_width = DMA_MEMORY_WIDTH_8BIT; dma_init_struct.number = BUF_LEN; dma_init_struct.periph_addr = USART_RDATA(USART0); 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 */ dma_channel_enable(DMA_CH2); /* USART DMA enable for transmission */ usart_dma_transmit_config(USART0, USART_DENT_ENABLE); /* enable DMA channel1 */ dma_channel_enable(DMA_CH1); } void uart0_init(uint32_t baud) { /* enable COM GPIO clock */ rcu_periph_clock_enable(RCU_GPIOA); /* enable USART clock */ rcu_periph_clock_enable(RCU_USART0); /* connect port to USARTx_Tx */ gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_9); /* connect port to USARTx_Rx */ 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_50MHZ, 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_50MHZ, GPIO_PIN_10); /* USART configure */ usart_deinit(USART0); usart_baudrate_set(USART0, baud); usart_stop_bit_set(USART0, USART_STB_1BIT); //设置停止位 usart_word_length_set(USART0, USART_WL_8BIT); //设置数据字长度 usart_parity_config(USART0, USART_PM_NONE); //设置奇偶校验位 usart_receive_config(USART0, USART_RECEIVE_ENABLE); usart_transmit_config(USART0, USART_TRANSMIT_ENABLE); usart_interrupt_enable(USART0, USART_INT_IDLE); usart_enable(USART0); uart0_dma_init(); nvic_irq_enable(USART0_IRQn, 1); } //本方法只适用发送字符串，不能发送0x00 void usart0_dma_send(char* buf) { memset(g_dma_tx_buf, 0x00, sizeof(g_dma_tx_buf)); strcpy(g_dma_tx_buf, buf); dma_channel_disable(DMA_CH1); dma_transfer_number_config(DMA_CH1, (uint32_t)strlen(g_dma_tx_buf)); /* enable DMA channel1 */ dma_channel_enable(DMA_CH1); } /* ********************************************************************************************************* * 函 数 名: USART0_IRQHandler * 功能说明: 串口0中断接收函数 * 形 参: 无 * 返 回 值: 无 ********************************************************************************************************* */ void USART0_IRQHandler(void) { uint8_t rx_num; if (RESET != usart_interrupt_flag_get(USART0, USART_INT_FLAG_IDLE)) { usart_interrupt_flag_clear(USART0, USART_INT_FLAG_IDLE); if (g_dma_rx_finish == 0) //数据没有处理完成，不接收新的字符 { dma_channel_disable(DMA_CH2); rx_num = sizeof(g_dma_rx_buf) - dma_transfer_number_get(DMA_CH2); memcpy(g_uart0_rx_buf, g_dma_rx_buf, rx_num); /* 转存数据到待处理数据缓冲区*/ memset(g_dma_rx_buf, 0x00, sizeof(g_dma_rx_buf)); /* 重新设置DMA传输 */ dma_memory_address_config(DMA_CH2, (uint32_t)g_dma_rx_buf); dma_transfer_number_config(DMA_CH2, sizeof(g_dma_rx_buf)); dma_channel_enable(DMA_CH2); /* 开启DMA传输 */ g_dma_rx_finish = 1; } } } |
