Bit Angle Modulation (BAM) in a PIC

[JEC]

I'd run in to the exact same issues between 127 and 128. Never had time to investigate it further.

My implementation just used a state machine in the interrupt routine - 1 state for each bit.

Each state sets TMR1 to a different level, then sets / clears the appropriate pins.

I assume that you're implementing the 2xF 'mirror' method in a similar way? Very clever.