UART rx length problem

[espOAK]

Hi,

I am trying to understand how to use uart_get_buffered_data_len().

My test code:

Code: [Select all] [Expand/Collapse]

1. uint8_t data[10];
2. int len;
3. const int uart_buffer_size = (1024 * 2);
4. QueueHandle_t uart_queue;
5.  
6. uart_config_t uart_config =
7. {
8.     .baud_rate = 9600,
9.     .data_bits = UART_DATA_8_BITS,
10.     .parity = UART_PARITY_DISABLE,
11.     .stop_bits = UART_STOP_BITS_1,
12.     .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
13.     .rx_flow_ctrl_thresh = 122,
14. };
15. ESP_ERROR_CHECK(uart_param_config(UART2, &uart_config));
16. ESP_ERROR_CHECK(uart_set_pin(UART2, 17, 16, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE));
17. ESP_ERROR_CHECK(uart_driver_install(UART2, uart_buffer_size, 0, 10, &uart_queue, 0));
18.  
19. [
20.     ... code, which send TX bytes. RX and TX pins connected together.
21. ]
22.  
23. // Get RX length
24. len = 0;
25. while (len == 0)
26. {
27.     ESP_ERROR_CHECK(uart_get_buffered_data_len(UART2, (size_t*)&len));
28. }
29.    
30. // Get RX byte
31. len = 0;
32. while (length != 1)
33. {
34.     len = uart_read_bytes(UART2, data, 1, 1);
35. }

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If I use the "Get RX length" part, the code get stuck forever in the while loop, but if I comment it out it works, ie there will be one rx byte read in the "Get RX byte" part.

Do I need to use uart_get_buffered_data_len() in some special way?