Chained modules except the rightmost do not change loop status or segment type on buttons presses

[qiemem]

Reported and discussed here: https://forum.mutable-instruments.net/t/stages-qiemems-alternative-firmware/17506/7?

[qiemem]

Thanks to pyerbass for the initial investigation.

Right module appears to work 100%.

Left module:

• All local functionality works:
  • Switching modes works fine
  • Functions 100% fine in ouroboros and DAHDSR mode.
  • Changes to segment property (polarity, range) work fine
• Right module recognizes gate inputs on left: a gate input on the left causes a looping ramp on the right to act like a repeated ramp instead of an LFO
• Left module accepts gate signals, transfers current segment correctly to right module, correctly identifies right module segment types, and outputs expected voltage.
• Module on right recognizes buttons presses from module on left: in a group, pressing a button on left and right simultaneously will cause the right segment to loop. The left segment does not loop however, and the module treats it like a single segment loop.

It looks like the problem is entirely in status change requests being passed back to the module on the left. Haven't figured out where the breakdown is yet in this process. It could be in transmitting the packet, receiving the packet, or handling the request. I've made the most changes to handling the request, but that code isn't different for remote vs local changes.

[qiemem]

Turned out to be a one character fix :stuck_out_tongue_closed_eyes:

For segment state update packets, the first 4 bits used to be used to indicate module index. For state change request packets, the first byte is used to indicate type, with the first 4 bits being 0xf, to distinguish from state updates.

Now, only the first 3 bits are used to indicate index (since one bit is dedicate to re-trigger/polarity), but the module was checking to see if the "index" was 0xf to see if the packet was a change request still. Since its only looking at three bits instead of 4, it needed to check for 0x7 instead.