STM32 MCUs feature at least a single ADC peripheral ... or you can just take “typical” values from the data sheet. For the F042 MCU these are 0x1FFFF7B8 for 30°C and 0x1FFFF7C2 for 110 ...

While somewhat trickier to set up and use than a GPIO peripheral, the U(S)ART of ST’s STM32 families is fairly uncomplicated to use, and immediately provides one with an easy way to communicate ...