RP2040 AT->USB QMK adapter questions
Posted: 19 Jun 2026, 14:19
I'm putting together an RP2040 keyboard adapter. Unfortunately, I'm not an electronics guy, so my skills are pretty much "follow directions and solder things."
The directions for wiring the AT keyboard to the pins on the 2040 are clear. You're supposed to add some 4.7K "pull-up resistors" to make the 3.3V 2040 pins output 5V. I can do that, but is that the optimal solution? Several people mentioned that the old IBM keyboards pull a lot of power, and sometimes USB adapters fail due to that. I don't have any problem with adding a dedicated 5V power supply if needed.
Is extra power a good idea, or is it overkill?
The directions for wiring the AT keyboard to the pins on the 2040 are clear. You're supposed to add some 4.7K "pull-up resistors" to make the 3.3V 2040 pins output 5V. I can do that, but is that the optimal solution? Several people mentioned that the old IBM keyboards pull a lot of power, and sometimes USB adapters fail due to that. I don't have any problem with adding a dedicated 5V power supply if needed.
Is extra power a good idea, or is it overkill?