Adafruit PCF8523 Real Time Clock Assembled Breakout Board
PCF8523 RTC breakout with battery backup for timekeeping when main power is removed. Communicates over I2C; operates at 3.3V or 5V supply and logic. Suitable for datalogging, alarms, and clock applications.
Pinout
- VCC
Power pin for the PCF8523 breakout. Adafruit Learn says to power it at the microcontroller logic level.
Type · powerVoltage · 3-5VDC input, same as logic level - GND
Common ground for power and logic.
Type · groundVoltage · 0V - SCL
I2C clock line.
Type · signalVoltage · logic level follows VCC - SDA
I2C data line.
Type · signalVoltage · logic level follows VCC - STEMMA QT
STEMMA QT connector on the STEMMA QT version for I2C/power chaining.
Type · connectorVoltage · carries VCC, GND, SCL, and SDA - SQW
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.
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