Great timer and shipping time was quick! If you are unfamiliar with python programming, running the test code will fail w/ I/O error if your boards EEPROM i2c address is 0x57. Just change the "at24c32_addr" variable to the correct one; in file SDL_D3231.py. A code comment would be helpful at line 79. You will also get another I/O error if you enable the timer as a RTC for the Raspberry pi and run the test code. If you use the tool i2cdetect -y 1 and the 0x68 address is shown as UU, it is blocked from access. I did not test it with Arduino library, wanted it as a rtc for the Pi. Thanks Switchdoc Labs.
Time adjustment pot difficult to set since no markings. Board is large for number of components. When connecting to a Pi need to ensure that you use a GPIO that is high impedance or OV on power up (not all of them are !). Otherwise the Watchdog works fine for me.