Page 1 of 1

ESP32 in connection with MCP23017

Posted: Sat May 01, 2021 4:23 pm
by Kymmenen
Hello,

I want to use the ESP32 in conneection with the MCP23017 port expansion via the I2C Bus.
From the internet I got some input for the connections which has to be used:

Vdd - 3.3V
Vss - GND
SCL - GPIO 22 and 3.3V via 2.1k pullup
SDA - GPIO 21 and 3.3V via 2.1k pullup
A0 - GND
A1 - GND
A2 - GND
Reset - 3.3V

I hope these connections are correct.

The problem now is that I do not get any output from the MCP23107.
Therefore I found a I2C scanner, to maybe identify the problem, on this website:
https://randomnerdtutorials.com/esp32-i ... duino-ide/

Running the scanner code I always get the result: No I2C devices found.

Measuring the voltage at SCL always results in constant 3.3V while using the scanner.

I hope somebody can help me to let the things work.
Thank you very much in advance!

Kymmenen