pico-ds3231

Kevin Boone, November 2022

What is this?

This is a simple C driver library for the DS3231 I2C real-time clock, for the Pi Pico. The library is completely self-contained, in the ds3231/ directory. See main.c for how to use it.

This isn't the only driver for the DS3231, but it might be the simplest. It only supports the time, date, and temperature functions -- there is not support for alarms or interrupts.

Wiring

The DS3231 can be connected to either of the Pico's I2C ports, using any of the pins that are supported. The user of library should specify which port and pins are in use. The defaults used by the test program are as follows:

Pico               DS3231 
----               --------
Pin 6 (SDA0)       Data / SDA
Pin 7 (SCL0)       Clock / SCL
Pin 36 (3.3V out)  Vcc / +
Pin 38 (GND)       Gnd / -

To run the test program with different wiring, change the pin assignments in config.h.

Building the test program

The usual, with the Pico SD:

mkdir build
cd build
PICO_SD_PATH=... cmake ..
make 

Using the test program

Copy the UF2 file to the Pico in the usual way, and run a terminal emulator. Enter 'get' to see the time, or 'set year month day hour minute second' to set it.

Sample output:

get
2022-11-27 09:21:00
temp=20.5000 deg. C