Some useful custom data channels if you prefer the old school OBD-II protocol:
Accelerator position (%)
PID: 0x22032b
Equation: B/2.0
(Surprisingly, the standard OBD PIDs for accelerator communicate values in some weird ranges. This PID gives data in a 0–200 range, but at least that looks deliberate)
Brake position (%)
OBD-II header: 0x760 (not sure if necessary, what's the default value?)
PID: 0x222b0d
Equation: max(0, bytesToInt(raw, 1, 2)) / 2.3
(You can try other multipliers if you find the number to be too high or too low for you. You can also wrap it with "min(100, ...)" to limit to 100%.)
Tire pressures, if your Miata has TPMS sensors (I believe earlier model year NDs had indirect TPMS only):
OBD-II header: 0x720
PIDs: 0x222a05 (FL), 0x222a07 (FR), 0x222a06 (RL), 0x222a08 (RR)
Equation: B * 1.373
You'll probably want to use the PIDs for tire pressures to be set up as "Slow channels". Their values don't change that often, and making them "Fast channels" would consume too much of the limited OBD-II bandwidth, negatively affecting the update rates for the more time-sensitive channels such as pedals.
