esotic UART baudrates won't work (IDFGH-1970)

[aster94]

Environment

• Development Kit: lolin32
• IDF version lasted used in the arduino framework
• Operating System: Windows
• Power Supply: USB

Problem Description

If i set a custom baudrate in the UART it won't work as expected. At first we tought the problem was in the arduino core (espressif/arduino-esp32#2004), but maybe it is not so I have been suggested to open an iussue here

Code to reproduce this issue

#include <Arduino.h>

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/uart.h"

#define ECHO_TEST_TXD (UART_PIN_NO_CHANGE)
#define ECHO_TEST_RXD (UART_PIN_NO_CHANGE)
#define ECHO_TEST_RTS (UART_PIN_NO_CHANGE)
#define ECHO_TEST_CTS (UART_PIN_NO_CHANGE)

#define BUF_SIZE 1024

void setup()
{
  uart_config_t uart_config = {
      .baud_rate = 10400,
      .data_bits = UART_DATA_8_BITS,
      .parity = UART_PARITY_DISABLE,
      .stop_bits = UART_STOP_BITS_1,
      .flow_ctrl = UART_HW_FLOWCTRL_DISABLE};
  uart_param_config(UART_NUM_2, &uart_config);
  uart_set_pin(UART_NUM_2, ECHO_TEST_TXD, ECHO_TEST_RXD, ECHO_TEST_RTS, ECHO_TEST_CTS);
  uart_driver_install(UART_NUM_2, BUF_SIZE * 2, 0, 0, NULL, 0);
}

void loop()
{
  const char *data = "test";
  uart_write_bytes(UART_NUM_2, data, 5);
  delay(2);
}

And here there are two logic analyzer data, the esp-idf.sr comes from the code above
test.zip

[negativekelvin]

@koobest 80M/0xFFFFF = 76

[negativekelvin]

It takes 5ms to send 5 bytes at 10400 so if you delay only 2ms you are going to overflow the tx buffer. But other than that, 10400 seems to work fine on uart 1&2.

[aster94]

Hi @negativekelvin if your buffer is not corrupted then or my esp32 is broken or i am doing something wrong in the code

This is a sample arduino code

#include <Arduino.h>

HardwareSerial ser(2);

void setup()
{
  ser.begin(10400, SERIAL_8O1);
}

void loop()
{
  ser.print("test");
  delay(100);
}

and here the corresponding version in idf code

#include <Arduino.h>

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/uart.h"

#define ECHO_TEST_TXD (GPIO_NUM_17)
#define ECHO_TEST_RXD (GPIO_NUM_16)
#define ECHO_TEST_RTS (UART_PIN_NO_CHANGE)
#define ECHO_TEST_CTS (UART_PIN_NO_CHANGE)
#define BUF_SIZE 1024

void setup()
{
  uart_config_t uart_config = {
      .baud_rate = 10400,
      .data_bits = UART_DATA_8_BITS,
      .parity = UART_PARITY_DISABLE,
      .stop_bits = UART_STOP_BITS_1,
      .flow_ctrl = UART_HW_FLOWCTRL_DISABLE};
  uart_param_config(UART_NUM_1, &uart_config);
  uart_set_pin(UART_NUM_1, ECHO_TEST_TXD, ECHO_TEST_RXD, ECHO_TEST_RTS, ECHO_TEST_CTS);
  uart_driver_install(UART_NUM_1, BUF_SIZE, 0, 0, NULL, 0);
}

void loop()
{
  uart_write_bytes(UART_NUM_1, "test", 4);
  delay(100);
}

I added the two logic traces in this zip file, and the pulseView program says me that there is a frame error
test2.zip

[aster94]

on the arduino core it was solved by espressif/arduino-esp32#3664
I am closing since i guess that also here have been solved but feel free to reopen it