DP8573A

Features:

Full function real time clockcalendar
--1224 hour mode timekeeping
--Day of week counter
--Parallel resonant oscillator
Power fail features
--Internal power supply switch to external battery
--Power Supply Bus glitch protection
--Automatic log of time into RAM at power failure
On-chip interrupt structure
--Periodic alarm and power fail interrupts

Pinout






Specifications






Description

The DP8573A is intended for use in microprocessor based systems where information is required for multi-tasking data logging or general time of daydate information .DP8573A is implemented in low voltage silicon gate microCMOS tech-nology to provide low standby power in battery back-up en-vironments The circuit's architecture is such that it looks like a contiguous block of memory or IO ports organized as one block of 32 bytes This includes the Control Registers the Clock Counters the Alarm Compare RAM and the Time Save RAM

Time and date are maintained from 1100 of a second to year and leap year in a BCD format 12 or 24 hour modes Day of week and day of month counters are provided Time is controlled by an on-chip crystal oscillator requiring only the addition of the 32768 kHz crystal and two capacitors Power failure logic and control functions have been integrat-ed on chip This logic is used by the RTC to issue a power fail interrupt and lock out the mP interface The time power
fails DP8573A  may be logged into RAM automatically when V_BB>V_CC Additionally two supply pins are provided When V_BB>V_CC internal circuitry will automatically switch from the main supply to the battery supply

The DP8573A's interrupt structure provides three basic types of interrupts Periodic AlarmCompare and Power Fail Interrupt mask and status registers enable the masking and easy determination of each interrupt