I2C No pull up found on SDA or SCL; check your wiring

Products & Technology XIAO
#1

Hi all!

there is a weird behavior when trying to use I2C with my XIAO boards (nrf, ESP32) in circuitpython:

RuntimeError: No pull up found on SDA or SCL; check your wiring

I do not have any issue when using Arduino code only in circuitpython!
Can someone tell me why and if there is some way to prevent the error without soldering resistors?

thx

#2

Hi there,
If you swap the SDA and SCL you will get that error also?
HTH
GL :slight_smile: PJ

1 Like
#3

thx a lot! one of the “wires” was loose :slight_smile:

I had the same issue with circuitpython and the rp2040 round display (waveshare) there it really was a software issue because it stated the wire error when trying to access the internal imu.

1 Like
#4

If you face this with a si7021 module:

There are 2 types sold- one with the pullup jumper already soldered (between the 2 resistors) and one where the 3 pads are separated - soldiering them will fix this issue! (as well as hooking up more i2c devices wich probably solved my old issue)