An Arduino library to control a Microchip MCP7940N or compatible Real Time Clock and Calendar.
Datasheet available here: http://ww1.microchip.com/downloads/en/DeviceDoc/20005010F.pdf
| MCP7940N | Arduino |
|---|---|
| SDA | SDA |
| SCL | SCL |
Timing can be controlled in one of two ways. First is to connect a 32.768 kHz crystal between pins X1 and X2. Or you can provide a 32.768 kHz clock signal to X1. Use SetExternalOscillatorEnabled() to switch between crystal and external clock.
MFP can be used as an interrupt for alarms (See examples/alarm.ino for details), as a square wave generator, or as a general purpose output.
VBAT can be connected to a battery to retain time if the main power goes down. Enable this with SetBatteryEnabled( true ). If not being used, it should be connected to GND.
This library uses the Wire library from Arduino. You must call Wire.begin() before attempting to use this library. You may also select the i2c bus speed by calling Wire.setClock()
View the examples folder for examples on usage.
See LICENCE.txt for license (MIT)