← All clocks

ESP-KVM is free, open-source firmware that turns an ESP32-P4 board into an IP-KVM: another computer's screen, keyboard and mouse in your browser, from the BIOS up. The DS3231 module - ZS-042 is an optional extra: a battery-backed clock that keeps the time across a power cut. What it does → Try the demo →

DS3231 module - ZS-042
Clock (optional)

DS3231 module - ZS-042

The common blue board with a CR2032 holder on the back. Four wires to the capture board's I2C bus.

StatusRun on hardware
ChipDS3231SN at 0x68, plus a 24C32 memory chip at 0x57
WiringVCC to 3V3, GND, SDA and SCL to the capture board's I2C bus
BatteryCR2032 or LIR2032
Settingfound by itself; Settings → System → Clock

The 24C32 memory chip sits at another address and is left alone. The pins on the far side pass the bus on, so a status OLED can hang off the same wires.

Good to know

  • Power it from 3V3, not 5V. Its pull-ups go to its own VCC, so 5V there puts 5V on the ESP32-P4's pins.
  • The battery. Most of these boards charge the cell through a diode and a resistor. With a plain CR2032 in it, take that diode off, or fit a rechargeable LIR2032.
  • The DS3231 chip is the one I run; this exact board I have not.