snowmanslick - My Snap TRRS cable doesn't seem ...
My Snap TRRS cable doesn't seem to be working?
I'm building the Snap and just got to the point where everything but the keyswitches are soldered in, and the guide tells me to test the board w/ Via's key matrix. Each half of the board seems OK. The LEDs are fine. But if I connect the two halves over TRRS and then to the computer, the LEDs on the side not plugged into USB light up, but shorting the keyswitch pins doesn't register any key presses.
I did a continuity check w/ my multimeter on the TRRS jacks. There's continuity between the TRRS cable and the solder pad on the PCB for each pin. One thing I find strange is that the jack furthest away from the microcontroller has the two middle rings of their jacks shorted together. This is true for both halves of the board. Is this expected? I tried looking for a schematic of the Snap, but can't seem to find one.
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Further question, is the TRRS cable hot-pluggable on these? What about the pogo pins? It's a bit difficult to test the pogo pins, since I haven't installed the acrylic spacer + magnets yet.
Some notes:
I'm using a Bit-C Pro (rp2040) with the nightly firmware release of (nullbitsco/snap/rp2040 - via) as linked from the firmware flashing guide:
https://github.com/nullbitsco/docs/blob/main/firmware/firmware_flashing.md
GitHub
docs/firmware/firmware_flashing.md at main · nullbitsco/docs
Online documentation (build guides, user manuals, etc) for nullbits products. - nullbitsco/docs
I was able to rig up something to test the pogo pins. Both halfs of the board seem to work when connected via pogo pins. But not TRRS.
Huh, after trying a few configurations, it seems that connecting the two halfs using only TRRS jacks in the middle of the board (furthest away from the microcontrollers) works. Both halfs of the board are recognized.
Q: Is there some known issue with the TRRS jacks under the microcontrollers? Are those ports not meant for connecting the keyboard halfs?
Solution
Unknown User•6mo ago
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Ah, thank you! Yes, everything is working great now!