I2C Scanner and WIO Terminal

Summary: Running an I2C Scanner finds devices for every I2C address on the WIO Terminal

Description: Anyone that has had I2C problems has probably run an I2C scanner such as the one on the Arduino playground at https://playground.arduino.cc/Main/I2cScanner/

I noticed an odd thing tonight when I ran it on my WIO Terminal expecting none of the addresses to be listed. Just the opposite happened… ALL the addresses came back as being seen.

This, of course, is completely wrong so I just wanted to let people know if they try it while debugging I2C issues.

Technically what is happening is that Wire.endTransmission() is returning 0 (success) for all the addresses when it should be returning 2 (a NACK on transmit of address). Real strange…

Hi @Dennis_Mabrey

It seems like this is a bug from the ArduinoSAMD core.

For simple usage, you can use this version: https://wiki.seeedstudio.com/Arduino_Software_I2C_user_guide/#i2c-scanner-for-arduino

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Thanks for that it will be useful.