MICROCHIP MCP795W20-I/SL

The MCP795WXX Real-Time Clock/Calendar (RTCC) tracks time using internal counters for hours, minutes, seconds, hundredth of seconds, days, months, years and day of week. Alarms can be configured on all counters up to and including months. For usage and configuration, the MCP795WXX supports SPI communications up to 5 MHz. The MCP795WXX is designed to operate using a 32.768 kHz tuning fork crystal with external crystal load capacitors. On-chip digital trimming can be used to adjust for frequency variance caused by crystal tolerance and temperature. SRAM and timekeeping circuitry are powered from the backup supply when main power is lost, allowing the device to maintain accurate time and the SRAM contents. The times when the device switches over to the backup supply and when primary power returns are both logged by the power-fail timestamp. The MCP795WXX features 128 bits of EEPROM which is only writable after an unlock sequence, making it ideal for storing a unique ID or other critical information. The MCP795WX1 and MCP795WX2 are preprogrammed with EUI-48 and EUI-64 addresses, respectively. Custom programming is also available. Two event detect modules are included on the MCP795WXX. The high-speed event detect module will generate an interrupt after a programmable number of pulses have been detected. The low-speed event detect module can be used to debounce mechanical switches and includes a selectable debounce period. The MCP795WXX also features an integrated Watchdog Timer peripheral. This allows applications to improve system robustness by moving this functionality outside of the microcontroller. The MCP795WXX has versatile output options. There is a dedicated pin for outputting a selectable frequency square wave or for use as a general purpose output. Additionally, the alarms can be assigned to either the Watchdog Timer interrupt output or the event detect interrupt output.

• Real-Time Clock/Calendar (RTCC):
  • Hours, minutes, seconds, hundredth of seconds, day of week, date, month, year
  • Leap year compensated to 2399
  • 12/24-hour modes
• Oscillator for 32.768 kHz Crystals:
  • Optimized for 6 - 9 pF crystals
• On-Chip Digital Trimming/Calibration:
  • ±1 ppm resolution
  • ±259 ppm range
• Dual Programmable Alarms
• Clock Output Function with Selectable Frequency
• Power-Fail Timestamp:
  • Time logged on switchover to and from Battery mode
• Wide Voltage Range:
  • Operating voltage range of 1.8V to 3.6V
  • Backup voltage range of 1.3V to 3.6V
• Low Typical Timekeeping Current:
  • Operating from VCC: 1.2 μA at 3.0V
  • Operating from VBAT: 1.0 μA at 3.0V
• Automatic Switchover to Battery Backup
• Programmable Watchdog Timer:
  • Dedicated output pin
  • Cleared via SPI bus or EVHS input
• Dual Configurable Event Detect Modules:
  • High-Speed Digital Event Detect for programmable pulse count detection
  • Low-Speed Event Detect for programmable switch debouncing
• 64-Byte Battery-Backed SRAM
• 1 Kbit or 2 Kbit EEPROM:
  • Software write-protect
  • Page write up to 8 bytes
  • Endurance: 1M erase/write cycles
• 128-Bit Protected EEPROM Area:
  • Robust write unlock sequence
  • EUI-48 MAC address (MCP795WX1)
  • EUI-64 MAC address (MCP795WX2)
• SPI Serial Interface:
  • SPI clock rate up to 5 MHz
• Temperature Range:
  • Industrial (I): -40°C to +85°C
• 14-Lead SOIC and TSSOP