【玩转ESP32】12、esp32串口使用

esp_err_t uart_driver_install(uart_port_t uart_num, int rx_buffer_size, int tx_buffer_size, int queue_size, QueueHandle_t* uart_queue, int intr_alloc_flags);

esp_err_t uart_param_config(uart_port_t uart_num, const uart_config_t *uart_config);

esp_err_t uart_set_rx_full_threshold(uart_port_t uart_num, int threshold);

esp_err_t uart_set_pin(uart_port_t uart_num, int tx_io_num, int rx_io_num, int rts_io_num, int cts_io_num);

int uart_read_bytes(uart_port_t uart_num, uint8_t* buf, uint32_t length, TickType_t ticks_to_wait);

int uart_write_bytes(uart_port_t uart_num, const char* src, size_t size);

#define EX_UART_NUM UART_NUM_1  //串口1

#define TXD_PIN    (GPIO_NUM_17) //txd使用gpio17
#define RXD_PIN    (GPIO_NUM_16) //rxd使用gpio16

#define BUF_SIZE (128)   //缓冲区定义
static QueueHandle_t uart_queue; //队列句柄
static uint8_t  uartbuf[BUF_SIZE];

void uart_comm_init(void)
{
    /* Configure parameters of an UART driver,
     * communication pins and install the driver */
    uart_config_t uart_config = {
        .baud_rate = 115200,
        .data_bits = UART_DATA_8_BITS,
        .parity = UART_PARITY_DISABLE,
        .stop_bits = UART_STOP_BITS_1,
        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
        .source_clk = UART_SCLK_APB,
    };
    //Install UART driver, and get the queue.
    uart_driver_install(EX_UART_NUM, BUF_SIZE * 2, BUF_SIZE * 2, 20, &uart_queue, 0);
    uart_param_config(EX_UART_NUM, &uart_config);
    uart_set_rx_full_threshold(EX_UART_NUM,126);

    //Set UART pins (using UART0 default pins ie no changes.)
    uart_set_pin(EX_UART_NUM, TXD_PIN, RXD_PIN, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);

    //Create a task to handler UART event from ISR
    xTaskCreate(uart_event_task, "uart_event_task", 2048, NULL, 12, NULL); //创建串口任务
}

static void uart_event_task(void *pvParameters)
{
    uart_event_t event;
    for(;;) {
        //阻塞接收串口队列，
        //这个队列在底层发送，用户只需在应用层接收即可
        if(xQueueReceive(uart_queue, (void * )&event, (portTickType)portMAX_DELAY)) {
            switch(event.type) {//各种串口事件
                case UART_DATA:
                    ESP_LOGI(TAG, "[UART DATA]: %d", event.size);
                    uart_read_bytes(EX_UART_NUM, uartbuf, event.size, portMAX_DELAY); //阻塞接收
                    ESP_LOGI(TAG, "[DATA EVT]:");
                    uart_write_bytes(EX_UART_NUM, uartbuf, event.size);//原样发送
                    break;
                //Event of HW FIFO overflow detected
                case UART_FIFO_OVF: //硬件fifo溢出
                    ESP_LOGI(TAG, "hw fifo overflow");
                    // If fifo overflow happened, you should consider adding flow control for your application.
                    // The ISR has already reset the rx FIFO,
                    // As an example, we directly flush the rx buffer here in order to read more data.
                    uart_flush_input(EX_UART_NUM);
                    xQueueReset(uart_queue);
                    break;
                //Event of UART ring buffer full
                case UART_BUFFER_FULL: //环形缓冲区满
                    ESP_LOGI(TAG, "ring buffer full");
                    // If buffer full happened, you should consider encreasing your buffer size
                    // As an example, we directly flush the rx buffer here in order to read more data.
                    uart_flush_input(EX_UART_NUM);
                    xQueueReset(uart_queue);
                    break;
                //Event of UART RX break detected
                case UART_BREAK:
                    ESP_LOGI(TAG, "uart rx break");
                    break;
                //Event of UART parity check error
                case UART_PARITY_ERR:
                    ESP_LOGI(TAG, "uart parity error");
                    break;
                //Event of UART frame error
                case UART_FRAME_ERR:
                    ESP_LOGI(TAG, "uart frame error");
                    break;
                //UART_PATTERN_DET
                case UART_PATTERN_DET:
                    break;
                //Others
                default:
                    ESP_LOGI(TAG, "uart event type: %d", event.type);
                    break;
            }
        }
    }
    vTaskDelete(NULL);
}