Issue with UART receive interrupt

[amalamal]

I Tried for UART receive interrupt in esp32, it is working with a controller, i can able to read the data what the controller sending through uart, But i connected esp 32 with one gsm module(quectel m66) here i cant able to read the uart receive data, It is not even receiving a single byte with same code i used with esp 32 and controller interface. The gsm module gpio high level is 2.8. I tried with one voltage level shifter also, we made the 2.8 output to 3.3 and given that to esp32 receive pin, still it didn’t receive a single byte.Anybody please give some suggestion to fix this issue.

[kolban]

I would suggest posting a schematic of how you have wired the ESP32 to your peripheral and some references to the data sheet of that peripheral. In addition, what is the nature of the application communicating with the peripheral? Did you write it? If not, where did it come from?

Also check the UART configuration including baud rate.

[ESP_Sprite]

FYI I took the liberty to make your title less shout-y. Please do not post titles in all caps.