@denneyjs I’ve found that, of the the 3 modes in which the QPQ operates, momentary and toggle modes aren’t particularly useful for what I need. Chord latching mode is more like what I want, but it has issues when the same note is played in multiple octaves. Also, even though the QPQ works in omni mode (all channels) it’s not channel-aware, so it can behave a little erratically when receiving data from multiple channels simultaneously. Finally, there’s no way to differentiate between an input CV plugged in with a voltage of 0 vs a voltage of 0 due to an input CV not being connected, which means that the LED display always shows activity for C for all 4 channels even if they are disconnected (as long as C is one of the MIDI notes selected to be quantized).
The last one is a hardware issue, but maybe there’s a software workaround. The others are just software issues, and can be fixed. I’ve spent some time completely rewriting the firmware, but have been taking a break from that. In the short term, I’ve just modified the existing firmware to work around some of the issues I’ve seen, and change the functionality of chord latching mode to be more in-line with how I want it to behave.