First attempt at extracting the stock Ignition Map

I've been doing some more fiddling with the stock ECU and can now control the RPM and AFM voltage going into it, and measure the spark angle coming out (using my STM dev board).

I wrote a little bit of code that steps the RPM and AFM voltage and spits the spark angle out of the UART.
I logged the UART data and inserted it into Excel and managed to produce this:

As before I've currently got TEN shorted to GND, and a fixed resistor for IAT (2k) and ECT (330R), and closed/wide-open throttle inputs left open.

Note that I've added 10 degrees to the angles to account for the stock static 10 degree offset.

I'll publish the raw data once I've done some more work and confirmed what I'm doing and what I think I'm measuring are correct.

One more note whilst I'm thinking about it - The ECU logs an error when the AFM voltage drops to 0.2V or lower.

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Update: Although the static timing is set at 10 degree on the MX5, I've just been looking at the spark outputs again - at idle with TEN and closed throttle shorted to GND (the conditions under which static timing is set on the engine)  the spark triggers at 3 degrees before the falling edge of the crank signal.
So, rather than being at -10 degrees, I think the falling edge of the crank signal is probably more like -7 degrees.
Though given that people often increase the advance by 2 to 4 degrees on the 1.6 engine my additional 10 degrees advance is probably about right!