UART not working on 3.3V

shaqlain garana
Posts: 6
Joined: Wed Feb 02, 2022 5:43 pm

UART not working on 3.3V

Postby shaqlain garana » Thu Feb 03, 2022 11:42 am

i am using esp wroom 32e custom board and having issue in uart communication when i am connecting a 3.3V uart device the console is showing nothing.

esp32 is simply not able to read the data( RX pin) although write function is working fine the other device receives (TX pin) the data correctly.

In simple word TX sending data properly but RX pin is not able read anything from the other device.

UART : UART0
TX_PIN = GPIO1
RX_PIN = GPIO3
baudrate : 9600
line resisteance >150 ohms

with thw samw config 5v devices are working without any issues.
please help me out to resolve the issue.
cheers :D :D

ESP_Sprite
Posts: 9716
Joined: Thu Nov 26, 2015 4:08 am

Re: UART not working on 3.3V

Postby ESP_Sprite » Fri Feb 04, 2022 4:57 am

Erm... you should not connect 5V devices directly to an ESP32; it's out of spec. Could be that you damaged the ESP32 pin, possibly.

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