WSAL19426 – Pico-RTC-DS3231/en

Documentation notice: This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

Summary

The Waveshare Pico-RTC-DS3231 is a real-time clock expansion module for the Raspberry Pi Pico series. It uses the precision DS3231 RTC chip over I²C and provides a battery holder, two programmable alarms, and a stackable design for adding more sensors.

Related products at JW Tech

WSAL19426 – Precision RTC Module for Raspberry Pi Pico, Onboard DS3231 Chip

Technical overview

Standard Pico header, compatible with the Raspberry Pi Pico series.
Onboard DS3231 chip with a backup-battery holder.
Tracks seconds, minutes, hours, date, day of week and year; leap-year compensation valid up to 2100.
Optional 24-hour or 12-hour format with an AM/PM indicator.
Two programmable alarm clocks.
Operating voltage: 3.3 V; backup battery: 2.3–5.5 V.
Operating temperature: −40 °C to 85 °C.
Standby power consumption approximately 100 nA to retain data and clock information.
The on-board LED is not used by default; solder a 0 Ω resistor at R8 to enable it.
The DS3231 INT pin is not used by default; solder 0 Ω resistors at R5, R6 or R7 to activate it.
R5 connects INT to Pico GP3 (alarm status), R6 to 3V3_EN (power-off) and R7 to RUN (reset).

Commands and examples – verify before use:

wget -P ~/pico https://files.waveshare.com/upload/5/5a/Pico-rtc-ds3231_code.zip
cd ~/pico && unzip Pico-rtc-ds3231_code.zip
cmake -DPICO_BOARD=pico -DPICO_PLATFORM=rp2040 ..
cmake -DPICO_BOARD=pico2 -DPICO_PLATFORM=rp2350 ..
make
sudo mount /dev/sda1 /mnt/pico && sudo cp rtc.uf2 /mnt/pico/ && sudo sync && sudo umount /mnt/pico && sleep 2 && sudo minicom -b 115200 -o -D /dev/ttyACM0

Notes and version constraints

The exact pin mapping and I²C address of the DS3231 are not explicitly stated in the source – verify against the schematic before soldering.
Flashing the official MicroPython firmware for Pico2 may cause the device to become unrecognized; use the alternative firmware from the package instead.
For the first upload via Arduino IDE, select the .uf2 board option first; only then will a COM port appear.
The source page contains placeholder variables ({{{name2}}} etc.) and outdated navigation lists; these have been removed.
No price, stock, or certification information was present in the source – no such claims were made.

Source and revision record

Pico RTC DS3231 - Waveshare Wiki
Source revision: 91417
Captured: 2026-09-01T04:15:49+00:00
SHA-256: 6d82f762bc81393cf6abac1174fd83e5c9ff9ef2ae5615beb644723d6dd095ea