Adafruit DS3231 Precision RTC Breakout
Pinout
- Vinheader
Main power input, use same voltage as microcontroller logic
Type · PowerVoltage · 2.3-5.5V - GNDheader
Common ground
Type · GroundVoltage · 0V - SCLheader / STEMMA QT
I2C clock with pullup
Type · I2CVoltage · Vin logic - SDAheader / STEMMA QT
I2C data with pullup
Type · I2CVoltage · Vin logic - BATheader/pad
Battery positive / backup supply connection
Type · PowerVoltage · 2.3-5.5V backup - 32Kheader/pad
32KHz oscillator output, open drain
Type · Signal - SQWheader/pad
Square wave or interrupt output, open drain
Type · Signal - RSTheader/pad
Reset/power-fail indicator, open drain
Type · Control
| Pin | Position | Type | Function | Voltage |
|---|---|---|---|---|
| Vin | header | Power | Main power input, use same voltage as microcontroller logic | 2.3-5.5V |
| GND | header | Ground | Common ground | 0V |
| SCL | header / STEMMA QT | I2C | I2C clock with pullup | Vin logic |
| SDA | header / STEMMA QT | I2C | I2C data with pullup | Vin logic |
| BAT | header/pad | Power | Battery positive / backup supply connection | 2.3-5.5V backup |
| 32K | header/pad | Signal | 32KHz oscillator output, open drain | |
| SQW | header/pad | Signal | Square wave or interrupt output, open drain | |
| RST | header/pad | Control | Reset/power-fail indicator, open drain |
Pin details
8 connections- Vinheader
Main power input, use same voltage as microcontroller logic
PowerVoltage · 2.3-5.5V - GNDheader
Common ground
GroundVoltage · 0V - SCLheader / STEMMA QT
I2C clock with pullup
I2CVoltage · Vin logic - SDAheader / STEMMA QT
I2C data with pullup
I2CVoltage · Vin logic - BATheader/pad
Battery positive / backup supply connection
PowerVoltage · 2.3-5.5V backup - 32Kheader/pad
32KHz oscillator output, open drain
Signal - SQWheader/pad
Square wave or interrupt output, open drain
Signal - RSTheader/pad
Reset/power-fail indicator, open drain
Control
RTC & timing
26 other optionsDS3231/DS3232 temperature-compensated RTCs, the budget PCF8523 and DS1307, the Si5351A clock generator (8kHz–160MHz), and bare 16MHz crystals — matched to drift tolerance and supply voltage.
16 MHz Quartz Crystal visual preview16 MHz Quartz Crystal
Adafruit PCF8523 Real Time Clock Assembled Breakout Board visual previewAdafruit PCF8523 Real Time Clock Assembled Breakout Board
Adafruit PCF8523 Real Time Clock Breakout Board visual previewAdafruit PCF8523 Real Time Clock Breakout Board
$4.95
Adafruit PiRTC - PCF8523 Real Time Clock for Raspberry Pi visual previewAdafruit PiRTC - PCF8523 Real Time Clock for Raspberry Pi
Adafruit PiRTC - Precise DS3231 Real Time Clock for Raspberry Pi visual previewAdafruit PiRTC - Precise DS3231 Real Time Clock for Raspberry Pi
Adafruit S-35710 Low-Power Wake Up Timer Breakout visual previewAdafruit S-35710 Low-Power Wake Up Timer Breakout
$4.95
Adafruit Si5351A Clock Generator with STEMMA QT visual previewAdafruit Si5351A Clock Generator with STEMMA QT
$7.95
ChronoDot - Ultra-precise Real Time Clock visual previewChronoDot - Ultra-precise Real Time Clock
DS1307 RTC Module with Battery for Raspberry Pi visual previewDS1307 RTC Module with Battery for Raspberry Pi
DS3231 Precision RTC FeatherWing - RTC Add-on For Feather Boards visual previewDS3231 Precision RTC FeatherWing - RTC Add-on For Feather Boards
Fermion: DS3231 Precise RTC (Breakout) visual previewFermion: DS3231 Precise RTC (Breakout)
Fermion: DS3231M MEMS Precise RTC (Breakout) visual previewFermion: DS3231M MEMS Precise RTC (Breakout)
Related groups
4 groups
10W Super Bright LED - Violet visual previewLED pixels
WS2812/SK6812 NeoPixel strips, rings and Jewels, APA102 DotStar pixels, and plain analog RGB strips — each matched to its protocol and host, not just its connector.
Components · Addressable LEDs · 180 parts
18-Channel 8-bit PWM LED Driver w/ I2C Interface visual previewBare ICs
74HC logic gates, MCP3008/MCP23017 ADCs and expanders, 24LC256 EEPROM, 4N25-series optocouplers and ULN2803A drivers — bare DIP chips with no breakout-board conveniences like pull-ups or level shifting.
Components · Integrated circuits · 68 parts
10-bit ADC (SPI) visual previewConverters
ADS1115/MCP3421 ADCs, MCP4725 and GP8413 DACs, CP2102 USB-UART boards, and I2C plumbing like the LTC4316 address shifter — matched to bus, resolution and signal range.
Components · Interface converters · 114 parts
256MB Micro SD Memory Card visual previewMemory
24LC32/25LC256 EEPROM, I2C FRAM, 64Mbit PSRAM, and microSD breakouts up to 64GB — matched to write frequency and data volume, not just interface.
Components · Memory & storage · 39 parts