Microchip Technology MCP795WXX/BXX RTCC time/calendar devices

The MCP795WXX/BXX RTCC range of stand-alone, real-time clock/calendar devices from MIcrochip, has a 10 MHz SPI interface, non-volatile memory.

The devices reduce component counts in the smart energy (eg, thermostats, power meters and commercial refrigeration); home appliance (eg, coffee makers, stoves and microwave ovens); motor vehicle (eg, dashboard controls, car radios and GPS); consumer electronic (eg, office equipment and video systems); and communications markets (eg, radios, cordless phones and network systems).

The devices have millisecond alarms and a 10 MHz SPI interface that supports very fast data access, resulting in longer MCU sleep and power-down modes and less power draw from the battery.

Other low power features include two event-detect inputs that draw minimal current in the RTCC device but wake the MCU when events such as a switch press or system tampering have occurred.

The devices include three types of non-volatile memory-EEPROM, SRAM and a unique ID - which can be ordered blank or with a pre-programmed MAC address.

Along with the automatic battery switchover for backup power, a power-fail time stamp logs the time and duration of any power failure and, for accurate timekeeping over a broad temperature range, the devices feature a wide digital-trimming range that compensates for crystal frequency drift over temperature.

In designs where a second low-frequency crystal is used, a boot-clock option provides a 32 kHz clock at power-up.