ESP32 Forum

Posted: **Mon Mar 21, 2022 9:27 pm**

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    static QueueHandle_t uart0_queue;
   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
    };
    // Install UART driver, and get the queue.
    uart_driver_install(UART_NUM_1, 1024, 1024, 20, &uart0_queue, 0);
    uart_param_config(UART_NUM_1, &uart_config);
    vTaskDelay(100 / portTICK_RATE_MS);
    uint32_t baudrate;
    ESP_LOGI("MAIN", "BAUD RATE 0: %d", baudrate);
    uart_get_baudrate(UART_NUM_1, &baudrate);
    ESP_LOGI("MAIN", "BAUD RATE 1: %d", baudrate);
    vTaskDelay(100 / portTICK_RATE_MS);
    uart_set_baudrate(UART_NUM_1, 230400);
    vTaskDelay(100 / portTICK_RATE_MS);
    uart_get_baudrate(UART_NUM_1, &baudrate);
    ESP_LOGI("MAIN", "BAUD RATE 2: %d", baudrate);
    vTaskDelay(100 / portTICK_RATE_MS);
    uart_set_baudrate(UART_NUM_1, 460800);
    vTaskDelay(100 / portTICK_RATE_MS);
    uart_get_baudrate(UART_NUM_1, &baudrate);
    ESP_LOGI("MAIN", "BAUD RATE 3: %d", baudrate);
    vTaskDelay(100 / portTICK_RATE_MS);
    uart_set_baudrate(UART_NUM_1, 921600);
    vTaskDelay(100 / portTICK_RATE_MS);
    uart_get_baudrate(UART_NUM_1, &baudrate);
    ESP_LOGI("MAIN", "BAUD RATE 4: %d", baudrate);

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The above code gives the following output

I (857) MAIN: BAUD RATE 0: 0
I (857) MAIN: BAUD RATE 1: 115201
I (1057) MAIN: BAUD RATE 2: 230423
I (1257) MAIN: BAUD RATE 3: 460929
I (1457) MAIN: BAUD RATE 4: 922190

Am I doing something wrong here ?

I am using latest docker image `espressif/idf:release-v4.4` and this is the only code in `app_main()`

Posted: **Mon Mar 21, 2022 10:46 pm**

approximation is to be expected due to divider and clock frequency limitations

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