uart_set_baudrate sets incorrect baud rate

[user91829]

Code: Untitled.c Select all

    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);

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()`

[WiFive]

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