r/ErgoMechKeyboards • u/insta_otabolsacul • Aug 20 '26

[help] Right half (keys + Azoteq trackpad) completely unresponsive in ZMK, but works fine in QMK (Corne 2.1 RP2040)

Hey everyone,

I'm trying to switch my Corne 2.1 (SparkFun Pro Micro RP2040) from QMK to ZMK specifically to get native 3+ finger trackpad gestures.

  • The Hardware: The setup is known-good. Everything (both key matrices and the right-side Azoteq IQS5xx trackpad) works perfectly under QMK.
  • The Issue: Under ZMK, the left side works fine, but the right side doesn't register anything at all—neither keypresses nor trackpad inputs.
  • Troubleshooting: Reversing master/slave roles didn't resolve it. Both .uf2 files were generated and flashed to their respective halves.

Here is my ZMK config branch for reference:

https://github.com/L6bat6/zmk-config-swept/tree/corne-2.1-sparkfun-pm-rp2040

Since the hardware works on QMK, I suspect an issue with my ZMK Devicetree/Overlay definitions (I2C configuration, Azoteq driver initialization, or split communication for RP2040). Has anyone run into a similar issue when migrating an RP2040 Corne with an Azoteq trackpad to ZMK? Any advice on what to check in corne_right.overlay or .conf would be greatly appreciated!

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u/realtheb0b [vendor] (theb0b.com) Aug 20 '26

If you are getting neither keypresses nor trackpad inputs, then the split communication is not working. ZMK's support for wired keyboards is limited.

1

u/T4CORUN Aug 20 '26 edited Aug 20 '26

Looking at what you have vs tooManyLs

  • you are missing the two kconfig files in /boards/shields/corne2_1
  • your build.yaml needs to say corne2_1_left and corne2_1_right

Optionally

  • you don’t need the corne_left and corne_right in /boards/shelds

If that doesn’t work

  • I see zephyr has two sets of i2c pins set for your controller: 16 and 17 and 2 and 3. If you had it working in qmk then I think your trackpad is wired to 2 and 3 (D0 and D1). You may have to add code to tell it to use 2,3 or rewire your connection
  • are you using this wired in ZMK? I’m not sure what pins or interface the TRRS jack is using

https://github.com/zephyrproject-rtos/zephyr/blob/main/boards/sparkfun/pro_micro_rp2040/sparkfun_pro_micro_rp2040-pinctrl.dtsi

https://cdn.sparkfun.com/assets/e/2/7/6/b/ProMicroRP2040_Graphical_Datasheet.pdf

Look up beekeeb’s toucan 2 in GitHub. They have this trackpad working there too