Real-Time Clocks keep track of day, date,
and time including century, year, month, hour, minutes, and seconds.
Many include Battery Switchover circuits, enabling them to keep
time even when power is off. Other timekeeping functions offered
include Alarm and Watchdog, and a calibration register supports
high accuracy requirements.
RTC options include supervisory functions such as Power-on
Reset/Low-Voltage Detect, Early Power-Fail Warning, Battery Monitor,
and more. Some parts such as the M41ST85 Non-Volatizor
can be used as NVRAM Supervisors by providing Battery Switchover
and Write Protection for external Low-Power SRAMs.
ST's popular Serial RTCs support both SPI and I2C
busses, and come in packages ranging from QFN16 and TSSOP8 to
ST's SNAPHAT® with removable/replaceable battery.
M41ST87Securitizor - Combination Serial RTC, Microprocessor Supervisor,
and NVRAM Controller with special security functions for Tamper
Detect and RAM Clear
