I think I understand.
You want a new ignition pulse, on two pins to replace the current single output on pin 4.
It looks like we now get an output pulse on pin 4 of some length and some repeating frequency determined by the RPM setting. It sound like you want to change this to an output on two pins.
The pulse width should change with rpm, I think I remember it does that now, and the time between the 2 pulses should change in relation to barWidth.
when all input pins of DAC get a 1 (+5v) the DAC output +12v (if powered by +12)
when all input pins of DAC get a 0 (gnd) the DAC output -12v (if powered by -12)
when pin5 of DAC get a 1 and others got a 0 the DAC output 0v
What I'm unclear of is how the two outputs to the DAC are timed. Is a +/- varying signal sent from the DAC to the module each cycle. Can you draw a timing diagram of how the 11 00 10 output states are sent to the DAC? Are they all sent in sequence during one output timing cycle?
It would help me if you could draw a timing diagram of the desired output pulses.
Can you explain about "barWidth". This variable does not appear in the previous code we worked on. What is it, and how does it relate to the timing of the 2 pulses.
In this new mode of output to the DAC, will the the return pulse from the module and the reading on the pin 2 interrupt be unchanged?
Will the charge pulse code be unchanged?
It's been awhile 