Trying to use tracedata pin as a gpio pin | ZMK | Page 1

fair bloom Dec 22, 2025, 3:04 AM

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I'm making a custom keyboard using a keyboard matrix, and I've been able to get all the keys to work except the keys in the row connected to D7/gpio0 11 (this is for a nicenano MCU). I looked at the nicenano schematic, it it seems like gpio0 11 is also labelled as a "tracedata" pin. Is it possible to use tracedata pins as gpio pins?

sturdy willow Dec 22, 2025, 3:18 AM

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It should work, it is not used for tracedata purpose by default. All the gpio pins broken out should be usable, unless you use them to something else like i2c or spi

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This might help you https://zmk.dev/docs/troubleshooting/hardware-issues#electrical-net-connections

Hardware Issues | ZMK Firmware

Troubleshooting common hardware issues.

fair bloom Dec 22, 2025, 4:01 AM

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I flashed my nicenano with the tester uf2 file and interestingly, pin7 was the only gpio pin that wasn't able to be printed out 🫠

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does this mean that my pin7 is broken?

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also, I don't think this is a wiring issue with my pcb - switches work correctly, diodes are all in the right direction, nothing is shorted

sturdy willow Dec 22, 2025, 6:58 PM

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fair bloom does this mean that my pin7 is broken?

Yeah, pretty much. It is possible to fry gpios by shorting them to 5v or battery, or by touching the soldering iron too long

#Trying to use tracedata pin as a gpio pin