The MCP795W12-I/SL is a low-power Real-Time Clock/Calendar (RTCC) uses digital trimming compensation for an accurate clock/calendar, an interrupt output to support alarms and events, a power sense circuit that automatically switches to the backup supply, non-volatile memory for safe data storage and several enhanced features that support system requirements. Along with a 32768kHz crystal, this RTCC tracks time using several internal registers and then communicates the data over a 5MHz SPI bus that is fast enough to support a programmable millisecond alarm. The device is fully accessible through the serial interface, while VCC is between 1.8 and 3.6V, but can operate down to 1.3V through the backup supply connected to the VBAT input for timekeeping and SRAM retention only. As part of the power sense circuit, a time saver function is implemented to store the time when main power is lost and again, when power is restored to log the duration of a power failure.
- Real-time clock/calendar (RTCC)
- On-chip digital trimming/calibration - ±255 PPM range in 1 PPM steps
- Clock-out function
- 2 Programmable alarms - supports IRQ or WDO
- Programmable open drain output - alarm or interrupt
- Power-fail time-stamp at battery switchover
- Logs time when VCC fails and VCC is restored
- Low operating current
- Backup power for timekeeping and SRAM retention
- 64-byte Battery-backed SRAM
- EUI-48? or EUI-64? MAC address
- 128-bit Unique ID in protected area of EEPROM - Unlock sequence for user programming
- Dual configurable event detect inputs
- Programmable watchdog timer
时钟与计时
