Hello! I’ve made pretty good progress with my project. I’m stuck on one last thing which I hope isn’t impossible 
I have a MicroMod Main Board - Single running an STM32 Processor. I am powering everything with an external, 6V lead acid battery. I am using a SparkFun Buck Regulator Breakout - 3.3V to regulate the 6V down to 3.3V before giving it to the Main Board. I soldered to the VBAT and GND plated through holes to provide this power. Everything seems to work well.
Now, I would like to measure the voltage of my 6V battery so that my device can estimate battery life. This is made more challenging because my battery is not directly connected. I don’t believe trying to infer the battery’s voltage after going through the buck regulator would yield good results.
So, I have an external voltage sensor which I want to connect to my device. I think I need to connect it to an analog-to-digital pin to be able to read it.
The description on the STM32 says, “Two Dedicated Analog Inputs, 15 total analog input capable inputs” but it’s not clear to me if any of those are exposed via the Main Board? They seem very clearly highlighted on the “SparkFun Thing Plus - STM32” but I don’t see anything similar here.
Is it possible for me to read the voltage of my 6V battery via STM32 + Main Board? If so, can I have some guidance? If not, is there an adapter or something that would allow me to do this - maybe through the QWIIC system or something? It looks like there are ADC via I2C converters. Maybe that’s the way to go?
Thanks