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.
Power pin for the PCF8523 breakout. Adafruit Learn says to power it at the microcontroller logic level.
Common ground for power and logic.
I2C clock line.
I2C data line.
STEMMA QT connector on the STEMMA QT version for I2C/power chaining.
Square-wave output pin when enabled.
| Pin | Type | Function | Voltage |
|---|---|---|---|
| VCC | Power | Power pin for the PCF8523 breakout. Adafruit Learn says to power it at the microcontroller logic level. | 3-5VDC input, same as logic level |
| GND | Ground | Common ground for power and logic. | 0V |
| SCL | I2C | I2C clock line. | logic level follows VCC |
| SDA | I2C | I2C data line. | logic level follows VCC |
| STEMMA QT | Unknown | STEMMA QT connector on the STEMMA QT version for I2C/power chaining. | carries VCC, GND, SCL, and SDA |
| SQW | Signal | Square-wave output pin when enabled. |
Power pin for the PCF8523 breakout. Adafruit Learn says to power it at the microcontroller logic level.
Common ground for power and logic.
I2C clock line.
I2C data line.
STEMMA QT connector on the STEMMA QT version for I2C/power chaining.
Square-wave output pin when enabled.
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