DESCRIPTION
The Portable System Controller is a circuit which incorporates many of the functions necessary for low power portable products integrated into one chip. The DS1677 provides a Real Time Clock, NV RAM controller, micro-processor monitor, power–fail warning, and a 3–channel, 8–bit analog–to–digital converter. Communication with the DS1677 is established through a simple 3–wire interface.

FEATURES
■ Provides Real Time Clock:
    - Counts seconds, minutes, hours, date of the month, month, day of the week, and year with leap year compensation valid up to 2100
    - Power control circuitry supports system power on from day/time alarm
■ Microprocessor monitor:
    - Halts microprocessor during power–fail
    - Automatically restarts microprocessor after power failure
    - Monitors push–button for external override
    - Halts and resets an out of control microprocessor
■ =NV RAM control:
    - Automatic battery backup and write protection to external SRAM
■ 3–channel, 8–bit analog–to–digital converter
■ Simple 3–wire interface
■ +5.0V operation
■ =1.25V threshold detector for power–fail warning