The ICM7170 real time clock is a microprocessor bus compatible peripheral, fabricated using Intersil’s silicon gate CMOS LSl process. An 8-bit bidirectional bus is used for the data I/O circuitry. The clock is set or read by accessing the 8 internal separately addressable and programmable counters from 1/100 seconds to years. The counters are controlled by a pulse train divided down from a crystal oscillator circuit, and the frequency of the crystal is selectable with the on-chip command register. An extremely stable oscillator frequency is achieved through the use of an on-chip regulated power supply.

Features

? 8-Bit, μP Bus Compatible

- Multiplexed or Direct Addressing

? Regulated Oscillator Supply Ensures Frequency Stability and Low Power

? Time From 1/100 Seconds to 99 Years

? Software Selectable 12/24 Hour Format

? Latched Time Data Ensures No Roll Over During Read

? Full Calendar with Automatic Leap Year Correction

? On-Chip Battery Backup Switchover Circuit

? Access Time Less than 300ns

? 4 Programmable Crystal Oscillator Frequencies Over Industrial Temperature Range

? 3 Programmable Crystal Oscillator Frequencies Over Military Temperature Range

? On-Chip Alarm Comparator and RAM

? Interrupts from Alarm and 6 Selectable Periodic Intervals

? Standby Micro-Power Operation: 1.2μA Typical at 3.0V and 32kHz Crystal

Applications

? Portable and Personal Computers

? Data Logging

? Industrial Control Systems

? Point Of Sale