Pinout
DS3231 RTC module (ZS-042, I2C) pinout
Pins
- 32K (32.768kHz output)
- SQW (square wave / alarm interrupt, active low)
- SCL
- SDA (I2C address 0x68)
- VCC (3.3–5V)
- GND
- CR2032 backup cell keeps time without power; remove the charging resistor for non-rechargeable cells on ZS-042 boards
- The 4 unpopulated pads on the opposite end repeat SCL, SDA, VCC and GND for chaining another I2C board
- On-board AT24C32 EEPROM on the same bus at 0x57 — the A0/A1/A2 solder jumpers lower that address
Specifications
| Supply voltage | Chip: 2.3–5.5 V; module typically used at 3.3–5 V |
|---|---|
| Interface | I2C, up to 400 kHz |
| I2C address | 0x68 (RTC); 0x57 for the on-board AT24C32 EEPROM by default |
| Accuracy | ±2 ppm from 0–40 °C (about ±1 minute per year); ±3.5 ppm from −40–85 °C |
| Oscillator | Built-in temperature-compensated crystal (TCXO) |
| Temperature sensor | Built in, ±3 °C accuracy, 0.25 °C resolution |
| Alarms | 2 time-of-day alarms on the SQW/INT pin |
| Outputs | 32 kHz output; SQW programmable 1 Hz–8.192 kHz |
| Backup battery | CR2032 holder (charging circuit on ZS-042 is meant for rechargeable LIR2032) |
| On-board EEPROM | AT24C32, 4 KB |
