This is an example program to get the time from a DS3231 'Real-Time Clock' module using an STM32 chip. It is simply set to blink an LED every 10 "seconds", whatever those are.
It also sets a number of variables and demonstrates read/writing to the EEPROM chips included on the cheap and popular 'ZS-042' DS3231 boards, but those values are not surfaced outside of a debugger.
The included Makefile has options for building the program for an STM32L031K6 or STM32F031K6 chip - there are "Nucleo" boards available with both of those cores. Note that pins B6 and B7 are labeled D5 and D4 respectively, on those boards.
Building and Uploading
You can build the code with
make, and upload it with the 'st-flash' utility:
st-flash write main.bin 0x08000000