The MCP79402 general purpose I2CTM Compatible real-time clock/calendar (RTCC) is highly integrated with memory and advanced features normally found in higher priced devices. These features include a battery switchover circuit for backup power, a timestamp to log power failures and digital trimming for accuracy. Using a low-cost 32,768 kHz crystal or other clock source, time is tracked in either a 12-hour or 24-hour format with an AM/PM indicator and timing to the second, minute, hour, day of the week, day, month and year. As an interrupt or wakeup signal, a multifunction open drain output can be programmed as an Alarm Out or as a Clock Out that supports 4 selectable frequencies. In addition to the SRAM memory, there a unique ID that is factory programmed in a locked section of EEPROM with a MAC Address. This ID can also be unlocked and reprogrammed by the end user.

  Low Power Operation

  VCC Min = 1.8V

  Icc

  Low Backup Power

  VBAT Min = 1.3V

  Ibat

  Automatic Battery Switchover with Timestamp

  VCC to VBAT (power lost)

  VBAT to VCC (power restored)

  Dual alarms with single Interrupt Output that operates on VCC or VBAT

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

  Digital Trimming Range from -127 to + 127 ppm in 1 ppm steps

  1 ppm is approximately 86 milliseconds/day

  EEPROM uses 8 bytes/page with Block Sector write protection

  Protect none, 1/4, 1/2 or all of array

  Unique ID is factory programmed with MAC Address