The MCP795W21 SPI RTCC is highly integrated with memory and advanced features normally found in higher priced devices. By starting with a basic real-time clock, digital trimming was added for higher accuracy, a battery switchover for backup power, a timestamp to log power failures and three types of memory, which includes SRAM, EEPROM and a unique ID in a locked section of EEPROM. This ID is preprogrammed with a 48-bit MAC Address, but it can also be ordered blank for the end user to program. By adding a watchdog timer and two programmable event detect inputs, lower power and more system robustness can be achieved by performaing these functions in the RTCC and allowing the MCU to sleep for longer periods of time.

  Low Power Operation

  VCC Min = 1.8V

  Icc

  Typical Standby Current

  Low Backup Power

  VBAT Min = 1.3V

  Ibat

  Typical Timekeeping & SRAM Retention Current

  Automatic Battery Switchover with Timestamp

  VCC to VBAT (VCC Lost)

  VBAT to VCC (VCC Restored)

  Dual configurable alarms with a 0.01 sec count on one alarm

  IRQ (VCC or VBAT)

  WDO (VCC)

  Clock Out frequencies: 32.768, 8.192 & 4.096 KHz and 1 Hz

  Digital Trimming Range from -255 to + 255 ppm in 1 ppm steps

  Adjusts up to 22 seconds/day

  Watchdog Timer - Dual Retriggers

  SPI Bus or EVHS digital input

  Dual Configurable Event Detects

  High speed with programmable pulse count (EVHS)

  Low speed with programmable debounce delay (EVLS)

  EEPROM has 8 Bytes/Page with Block Sector write protection

  Protect: None, 1/4, 1/2 or all of array

  Factory standard MAC address programming or custom ID available