ChronoDot - Ultra-precise Real Time Clock

RTC breakout based on the MAX31328 temperature-compensated oscillator (TCXO); pin- and code-compatible with DS3231-based ChronoDots. Communicates over I2C; battery-backed to maintain time when main power is removed.

VCC
Main supply input for the ChronoDot when connected to a microcontroller; official macetech docs say VCC powers the module during controller use.
Type · powerVoltage · 2.3V to 5.5V DC per official macetech ChronoDot V3 documentation.
GND
Ground reference for the ChronoDot supply and I2C interface.
Type · groundVoltage · 0V
BAT
Battery node connected directly to the CR1632 cell; official docs say it can be used for an external battery or battery-health monitoring and must not be shorted.
Type · powerVoltage · 3V lithium CR1632 battery node per official macetech documentation.
SDA
I2C serial data line used to communicate with the ChronoDot RTC and onboard EEPROM.
Type · i2c
SCL
I2C serial clock line used to communicate with the ChronoDot RTC and onboard EEPROM.
Type · i2c
RST
Active-low reset signal; official docs state it asserts below about 2.5V VCC or when externally pulled low, without affecting timekeeping.
Type · resetVoltage · Active-low; asserts when VCC is less than about 2.5V per official docs.
SQW
Configurable square-wave or alarm-trigger output; official docs list 1 Hz, 1024 Hz, 4096 Hz, and 8192 Hz modes and note it needs a pull-up to VCC when used.
Type · digital outputVoltage · Open-drain style output requiring pull-up to VCC when used; 10K suggested by official docs.
32K
32768 Hz open-drain clock output for use as an accurate oscillator reference when enabled.
Type · clock outputVoltage · Open-drain output requiring pull-up resistor per official docs.

Pin	Type	Function	Voltage
VCC	power	Main supply input for the ChronoDot when connected to a microcontroller; official macetech docs say VCC powers the module during controller use.	2.3V to 5.5V DC per official macetech ChronoDot V3 documentation.
GND	ground	Ground reference for the ChronoDot supply and I2C interface.	0V
BAT	power	Battery node connected directly to the CR1632 cell; official docs say it can be used for an external battery or battery-health monitoring and must not be shorted.	3V lithium CR1632 battery node per official macetech documentation.
SDA	i2c	I2C serial data line used to communicate with the ChronoDot RTC and onboard EEPROM.
SCL	i2c	I2C serial clock line used to communicate with the ChronoDot RTC and onboard EEPROM.
RST	reset	Active-low reset signal; official docs state it asserts below about 2.5V VCC or when externally pulled low, without affecting timekeeping.	Active-low; asserts when VCC is less than about 2.5V per official docs.
SQW	digital output	Configurable square-wave or alarm-trigger output; official docs list 1 Hz, 1024 Hz, 4096 Hz, and 8192 Hz modes and note it needs a pull-up to VCC when used.	Open-drain style output requiring pull-up to VCC when used; 10K suggested by official docs.
32K	clock output	32768 Hz open-drain clock output for use as an accurate oscillator reference when enabled.	Open-drain output requiring pull-up resistor per official docs.

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