Modbus RTU problem with de signal

[luk_ab]

I'm using the modbus master example, since I'm having problems with the communication of my device I examined the signals on the TX RX and DE pins. Below you can see that the EN signal goes low before TX finishes transmitting.

logic

Logic_KFOZGr5i7a.png (105.27 KiB) Viewed 1760 times

How can I fix this? Modbus speed 9600 TX - GPIO23 RX - GPIO22 DE - GPIO18

[ESP_alisitsyn]

Hi @luk_ab,

Which version of esp-idf you are using? The issue you describe looks as already resolved issue with the UART driver in RS485 mode.

[luk_ab]

Hi @ESP_alisytsyn in this project I am using ESP-IDF v5.1.2 communication I run on UART 2. I momentarily coped by using a separate task to control the DE pin. From which version of IDF does this work correctly?

[ESP_alisitsyn]

Hi @luk_ab,

Sorry for the late response.
As per my information the issue is fixed by commit https://github.com/espressif/esp-idf/co ... 9338ccdf37