ESP32+RS485参考代码要点+@环境esp-idf-v5.1.2 +vscode 草稿

在环境esp-idf-v5.1.2 +vscode 中，如何在一个文件内，调用另外一个文件夹内定义的函数。

设置帧内间隔（ 在传输线上，两个发送的字节之间的时间间隔，不超过3.5发送单个字节的时间。）
通过函数 esp_err_t uart_set_rx_timeout(uart_port_t uart_num, const uint8_t tout_thresh)实现此功能。

在RTOS中，主机发送查询命令后，一般可以阻塞等待从机应答。这个阻塞接收应答的函数可以由uart_read_bytes(）实现。此函数用法：
int len = uart_read_bytes(uart_num, data, BUF_SIZE, PACKET_READ_TICS);
其中：#define PACKET_READ_TICS        (100 / portTICK_PERIOD_MS)

/**
 * @brief UART set threshold timeout for TOUT feature
 *
 * @param uart_num     Uart number to configure, the max port number is (UART_NUM_MAX -1).
 * @param tout_thresh  This parameter defines timeout threshold in uart symbol periods. The maximum value of threshold is 126.
 *        tout_thresh = 1, defines TOUT interrupt timeout equal to transmission time of one symbol (~11 bit) on current baudrate.
 *        If the time is expired the UART_RXFIFO_TOUT_INT interrupt is triggered. If tout_thresh == 0,
 *        the TOUT feature is disabled.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_ERR_INVALID_STATE Driver is not installed
 */
esp_err_t uart_set_rx_timeout(uart_port_t uart_num, const uint8_t tout_thresh);

举例 初始化为半双工RS485工作模式

/**
 * @brief       初始化RS485
 * @param       串口编号
 * @retval      无
 */
void mcu_rs485_init(uint16_t ncom)
{
    uint16_t uart_num = 0;
    uart_num =ncom;
    uart_config_t uart_config = {
        .baud_rate = BAUD_RATE,
        .data_bits = UART_DATA_8_BITS,
        .parity = UART_PARITY_DISABLE,
        .stop_bits = UART_STOP_BITS_1,
        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
        .rx_flow_ctrl_thresh = 122,
        .source_clk = UART_SCLK_DEFAULT,
    };

    // Set UART log level
    esp_log_level_set(TAG, ESP_LOG_INFO);

    ESP_LOGI(TAG, "Start RS485 configure UART.");

    // Install UART driver (we don't need an event queue here)
    // In this example we don't even use a buffer for sending data.
    ESP_ERROR_CHECK(uart_driver_install(uart_num, BUF_SIZE * 2, 0, 0, NULL, 0));

    // Configure UART parameters
    ESP_ERROR_CHECK(uart_param_config(uart_num, &uart_config));

    ESP_LOGI(TAG, "UART set pins, mode and install driver.");

    // Set UART pins as per KConfig settings
    ESP_ERROR_CHECK(uart_set_pin(uart_num, ECHO_TEST_TXD, ECHO_TEST_RXD, ECHO_TEST_RTS, ECHO_TEST_CTS));

    // Set RS485 half duplex mode
    ESP_ERROR_CHECK(uart_set_mode(uart_num, UART_MODE_RS485_HALF_DUPLEX));

    // Set read timeout of UART TOUT feature  3.5 bytesTime  ECHO_READ_TOUT =3
    ESP_ERROR_CHECK(uart_set_rx_timeout(uart_num, ECHO_READ_TOUT));

    // // Allocate buffers for UART
    // uint8_t* data = (uint8_t*) malloc(BUF_SIZE);

    ESP_LOGI(TAG, "UART %d ready.\r\n", uart_num);
    //echo_send(uart_num, "Start RS485 UART test.\r\n", 24);
}