What is the ADC input vRef voltage?
Spec sheet (https://raw.github.com/spark/core/master/Datasheets/ST_STM32F103CB.pdf) says between 2.4 and the actual Vdda / VIN with a max of 3.6v.
This matters as the spec sheet calls out the ADC divides up it’s LSBs based on the “ideal” formula of vRef / 4096. I’m taking that with a shaker full of salt as most of the TI range of ADCs don’t have a self correcting vREF external reference, ADS1119 is a new example of one that does.
Knowing the theoretical LSB / mV ratio (with gain/offset calcs) makes it easier to map exactly the ADC result to mV and then to resistance for temperature sensing.