ChronoDot - Ultra-precise Real Time Clock

ChronoDot - Ultra-precise Real Time Clock — Adafruit — 255

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.

Pinout

Logical pinout · physical placement not verified
CHRONODOT - ULTRA-PRECVCCSCLGNDRSTBATSQWSDA32K
  • 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 · ControlVoltage · 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 · GPIOVoltage · 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 · SignalVoltage · Open-drain output requiring pull-up resistor per official docs.

RTC & timing

26 other options

DS3231/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.

View all 26

Related groups

4 groups