I have narrowed my issue down to a change in the function uart_set_pin() in esp_driver_uart/src/uart.c from 5.4.2 to 5.5.1.
If I replace the uart_set_pin() in 5.5.1 with the 5.4.2 version the uart_echo_rs485 test example program (with my mods) works fine with UART RX.

Specifically if I add the gpio ...

One thing to note is that the Waveshare ESP32-S3 4.3 hardware uses the following pins for RS485:

RS485_RX: GPIO43
RS485_TX: GPIO44

It has a hardware circuit so no RS485 TX enable line is needed.
In the ESP32-S3 documentation under pinmux, it does say these lines could be used for debugging over U0 ...

Hi,

I am working on code that is running on a Waveshare ESP32-S3 4.3. This has the ESP32-S3 CPU on it. In general I have things working well while using IDF 5.4.2 with lvgl display, I2C touch and RS485 communications at 9600 Baud. However there were some occasional issues (crashes, probably due to ...

Its a great shame so many ESP32 IO pins have weak pull-ups enabled by default. I am producing a low power, battery powered system and some of these lines are driving the gates of MOSFET's to turn on high current devices. It's not nice these power on after a reset. I will have to move those lines to ...

Ah, I see the default pullup/pulldowns are defeined in the ESP32 datasheet, not the ESP32-PICO-V3 datasheet.

Many thanks.
I will need to use a different pin
Is there any info on which pins have pull-ups/pull-downs by default ?

Hi,

I am just testing a new ESP32-PICO-V3 board that I have designed. It is generally working, but I have an issue with the Pin28 SD2/IO9 line. According to the datasheet this pin is usable as a GPIO line. Indeed it looks like I can drive this as an output.

However, it looks like by default when ...

Hi,
We have developed a board that uses the ESP32_PICO_D4 chip/module. All is working fine with the chip but we now need to go through CE testing. We are trying to use the ESP_RF_test_tool_v1.1.0 and specifically the ESP32_RF_TEST_BIN_V1.4.6_20181019.bin firmware that provides the ability to set the ...