CircuitPython and onboard OLED: pullups requested for SDA/SCL (I2C)

[thymjan]

I'm running in an issue with CircuitPython: Can't use the onboard OLED-display without pullups.
A similar topic was discussed here:
[https://github.com/adafruit/circuitpython/pull/4488#]

SDA=board.GP6
SCL=board.GP7
i2c = busio.I2C(SLC, SDA)

Is there a way to activate the internal pullups?

[dhalbert]

Replied also in adafruit/circuitpython#4488 (comment). This is probably the better place for discussions on the PiSquare specifically.

The internal pullups on an RP2040 are quite weak (50k-80k) and not very good for I2C. All of the I2C breakouts Adafruit makes have on-board pullups. We don't add pullups to the microcontroller boards.

It looks like (https://cdn.shopify.com/s/files/1/1217/2104/files/Schematic_9f818051-fdfc-43dd-9e5e-0999f1dc1d1c.pdf?v=1657287360) GPIO7 and GPIO6 are used for I2C. Since those pins are available on the 2x20 header, I think you could add some external pullups from those pins to 3.3V without too much work.

It would be nice if this board had external pullups on the I2C pins. If you don't want them pulled up all the time, the pullup voltage could be supplied by another GPIO pin.

[thymjan]

I've already made a little shim:

This is working. But I don't get the point why there is no option in CircuitPython to activate the internal pullups for I2C.
With MircoPython I can use the onboard display without the external pullups.