MCP795Wxx Real-Time Clock / Calendars

By Microchip Technology 218

MCP795Wxx Real-Time Clock / Calendars

Microchip's real-time clocks are highly integrated with non-volatile memory and cost effective features for real life applications. This includes a battery switchover with timestamp to maintain timekeeping in order to log the time and duration of any power failure. When higher accuracy is necessary, digital trimming compensates for crystal frequencies that drift over temperature.

The MCP795Wxx series are accurate real-time clock devices that use an external 32.768 KHz crystal as a timing source. Most RTCCs use a crystal for timing with the understanding that all crystals drift in frequency over temperature.

  • Three types of user memory:
    • SRAM: 64 bytes
    • EEPROM: 1 and 2 Kbits
    • Unique ID: 128 bits
  • Alarms: counts down to 0.01 seconds
  • Watchdog timer:
    • Dual retriggers using SPI bus or GPIO
    • From 15 msec to 64 sec
  • Digital trimming: adjustment range of approximately 22 seconds/day
  • Event detect inputs:
    • High speed - programmable count
    • Low speed - programmable debounce
  • Boot clock (boot devices only): 32 KHz clock output at powerup
  • Operating speed: 10 MHz @ 4.5 V