Yes, you would need to calibrate it to get voltage offset and scalar, then you can output correct voltage as V/Oct pitch CV. Your idea of calibration sounds almost correct, I think that current procedure for Lich relies on calibrating output with a multimeter, then using calibrated output as voltage generator to calibrate input.
Converting pitch CV to frequency is explained here: https://community.rebeltech.org/t/pure-data-conversion-v-oct-to-frequency/987/2?u=antisvin
To go the other way around and generate CV you'd need:
- get number of volts = log2(FREQUENCY/440) , where 440 is your base frequency (can multiply or divide this by anything that is a power of 2 to get different base octave)
- count the DAC value as out = volts / multiplier + offset
I suspect Martin has a stashed sample of PD code that does it, but this info should be added to our PD docs too.