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