8-bit USB serial protocol for Arduino, with apologies to MIDI
as used in Fake8 SimHub plugin and PWM_FullConfiguration Arduino sketch for e.g. PWM tension testing
/*
; 4 msb of first byte in command sequences
; 1 == msb: command; 2 bytes for 110x and 100x
; 110x == 3 msb: 1 command with 12-bit value in 2 bytes
; 100x == 3 msb: 32 commands with 7 bits in second byte as value
; 111x == 3 msb: 8 commands with 7 bits from second and third byte as 16-bit value
; 101x == 3 msb: 31 commands with second byte as 7-bit count of following 7-bit values.
; 1011 1111: reset in 1 byte
*/