High Resolution Thermistor Readings without the ADC

With a slight modification, Nick Gammons capacitance measuring method


can be used to read resistive sensors, and after some testing I've found that this ICU based approach can deliver higher resolution thermistor readings than the 16-bit oversampling we've been using to date.


This can be generalized to ANY resistive sensor that's not affected too much by self heating during the RC rise time. The process is ratiometric, but as with the oversampling calibrations, I'm still leaning on the S&H constants to absorb the self heating offset, and the other miscellaneous temperature coefficients in the system.

Works well.