MCP7940 Real Time Clock Breakout Board

This is a breakout board for the Microchip MCP7940 Real Time Clock and Calendar chip featured on the I2C and SPI Education Shield and is compatible with all the associated Rheingold Heavy tutorials.

The awesome chip gives you a clock and calendar output that you can use to time and stamp anything that happens to your microcontroller. Infrared beam interrupted with someone sneaked into your room? Time stamp. Temperature got too warm or cold? Time stamp. But it’s so much more than time stamps! The MCP7940 also has an extensive alarm system, so you can set a time for it to trigger your microcontroller to do something. No more having to wait 15quadrigintillion milliseconds before doing something, just set an alarm for 08:27:31 8-MAR 2016 and let the RTC handle the rest.

The big wide spot allows you to slot in a CR2032 LiON coin cell battery to use as battery backup if your V_CC source gets disconnected for a period of time. Just slide the batter in and set the appropriate register, and you can sit disconnected for quite a while before you have to worry about your chip resetting to defaults.

Even better, the MCP7940 Real Time Clock provides a way of trimming the time to prevent variations from the oscillator causing a fast or slow running time. Just modify the configuration register to eliminate or add clock cycles and you’ll be ticking away perfectly.

Link to MCP7940 Datasheet