ESP32-C3入门教程基础篇⑤——UART串口通信

╰半橙微兮° 2022-09-11 08:20 843阅读 0赞

### 文章目录 ###

*  一、前言
 *  二、快速运行
 *  三、硬件接线
 *  四、运行效果
 *  五、初始化
 *  六、发送线程
 *  七、接收线程

# 一、前言 #

> 本文基于VS Code IDE进行编程、编译、下载、运行等操作  
> 基础知识点请查阅：[ESP32-C3入门教程 基础篇①——基于VS Code构建Hello World][ESP32-C3_ _VS Code_Hello World]

# 二、快速运行 #

*  示例项目中，选择`peripherals`—>`uart`—>`uart_async_rxtxtasks`
 *  `menuconfig`配置`ESP32C3-Specific`—>`Rec 0`
 *  芯片选择`ESP32-C3(Built-in USB JTAG)`
 *  快速运行`ESP-IDF Build, Flash and Monitor`（左下角）

# 三、硬件接线 #

*  TX/RX 两个pin可以在代码修改

TX-GPIO4

GND

RX-GPIO5

USB

ESP32-C3

USB转TTL

PC电脑

# 四、运行效果 #

*  串口调试助手
    
     *  每2秒打印一行`Hello world`
 *  VS Code ESP-IDF Monitor
    
     *  每秒打印一行`TX_TASK: Wrote 13 bytes`
     *  在串口调试助手发送`hello weijian`时，会显示`RX_TASK: Read 16 bytes: 'hello weijian`

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5bCP5bq35biI5YWE_size_20_color_FFFFFF_t_70_g_se_x_16]

# 五、初始化 #

*  串口初始化（波特率、数据位、停止位、校验位）
 *  创建并启动发送线程
 *  创建并启动接收线程

static const int RX_BUF_SIZE = 1024;
    
    #define TXD_PIN (GPIO_NUM_4)
    #define RXD_PIN (GPIO_NUM_5)
    
    void init(void) { 
        const 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,
        };
        // We won't use a buffer for sending data.
        uart_driver_install(UART_NUM_1, RX_BUF_SIZE * 2, 0, 0, NULL, 0);
        uart_param_config(UART_NUM_1, &uart_config);
        uart_set_pin(UART_NUM_1, TXD_PIN, RXD_PIN, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
    }
    
    void app_main(void)
    { 
        init();
        xTaskCreate(rx_task, "uart_rx_task", 1024*2, NULL, configMAX_PRIORITIES, NULL);
        xTaskCreate(tx_task, "uart_tx_task", 1024*2, NULL, configMAX_PRIORITIES-1, NULL);
    }

# 六、发送线程 #

int sendData(const char* logName, const char* data)
    { 
        const int len = strlen(data);
        const int txBytes = uart_write_bytes(UART_NUM_1, data, len);
        ESP_LOGI(logName, "Wrote %d bytes", txBytes);
        return txBytes;
    }
    
    static void tx_task(void *arg)
    { 
        static const char *TX_TASK_TAG = "TX_TASK";
        esp_log_level_set(TX_TASK_TAG, ESP_LOG_INFO);
        while (1) { 
            sendData(TX_TASK_TAG, "Hello world\r\n");
            vTaskDelay(2000 / portTICK_PERIOD_MS);
        }
    }

# 七、接收线程 #

static void rx_task(void *arg)
    { 
        static const char *RX_TASK_TAG = "RX_TASK";
        esp_log_level_set(RX_TASK_TAG, ESP_LOG_INFO);
        uint8_t* data = (uint8_t*) malloc(RX_BUF_SIZE+1);
        while (1) { 
            const int rxBytes = uart_read_bytes(UART_NUM_1, data, RX_BUF_SIZE, 1000 / portTICK_RATE_MS);
            if (rxBytes > 0) { 
                data[rxBytes] = 0;
                ESP_LOGI(RX_TASK_TAG, "Read %d bytes: '%s'", rxBytes, data);
                ESP_LOG_BUFFER_HEXDUMP(RX_TASK_TAG, data, rxBytes, ESP_LOG_INFO);
            }
        }
        free(data);
    }

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[ESP32-C3_ _VS Code_Hello World]: https://blog.csdn.net/kangweijian/article/details/120284617
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5bCP5bq35biI5YWE_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/66c7860adc524faf865533b83e7f9011.png