Microchip has released an application note outlining usage of their serial RTCC devices.
Many embedded systems require some form of accurate
timekeeping. There are a growing number of applications
that require an external Real-Time Clock/
Calendar (RTCC) and higher integration of external
peripheral components into the RTCC. In order to
achieve a highly robust and repeatable system, the
designer must consider the rest of the system components
including pull-up resistor values and the crystal
selection. There are a number of situations that can
result in less than optimal operation, many of which are
easy mistakes that are avoidable with some initial
knowledge. The most important of these are discussed
in this application note.This application note provides assistance and
guidance in using the Microchip RTCC family of
devices. This application note covers the I2C™
(MCP794XX) family of devices.
The MCP794XX family datasheet can be found here.