Real-time clock/calendar: Both ICs provide accurate timekeeping, tracking seconds, minutes, hours, day of the week, date, month, and year. They also automatically adjust for months with fewer than 31 days and leap years.Battery backup: Both chips include an internal battery to maintain time and data even when the primary power supply is off.On-chip RAM: Both feature battery-backed static RAM for storing user data. The DS12C887+ has 113 bytes of RAM, while the DS12B887 has 114 bytes.Programmable Interrupts: Both offer three independently maskable interrupt flags for various timing needs, such as a time-of-day alarm and periodic interrupts. The periodic interrupt rates can be programmed from 122 µs to 500 ms.Programmable Square Wave Output: Both can generate a programmable square wave output signal (SQW). The frequency of the SQW pin can be changed by programming Register A.Multiplexed Bus Interface: Both are accessed through a multiplexed byte-wide interface.Automatic Power-Fail Detect: Both chips include circuitry that detects a power failure and automatically switches to the battery backup, protecting time and data during power outages.Operating Voltage: Both operate within a supply voltage range of 4.5V to 5.5V.Daylight Saving Time Option: Both have an option to account for Daylight Savings Time.
