Description
The DS12C887 real-time clocks (RTCs) are designed to be direct replacements for the DS1287. The devices provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 113 bytes of battery-backed static RAM. The DS12C887 adds a century byte at address 32h. For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The devices also operate in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. The device is accessed through a multiplexed byte-wide interface, which supports both Intel and Motorola modes.
Key Features
Drop-In Replacement for IBM AT Computer Clock/Calendar
RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Through 2099
Binary or BCD Time Representation
12-Hour or 24-Hour Clock with AM and PM in 12-Hour Mode
Daylight Saving Time Option
Selectable Intel or Motorola Bus Timing
Interfaced with Software as 128 RAM Locations
14 Bytes of Clock and Control Registers
113 Bytes of General-Purpose, Battery-Backed RAM
RAM Clear Function
Interrupt Output with Three Independently Maskable Interrupt Flags
Time-of-Day Alarm Once Per Second to Once Per Day
Periodic Rates from 122µs to 500ms
End-of-Clock Update Cycle Flag
Programmable Square-Wave Output
Automatic Power-Fail Detect and Switch Circuitry
Optional Industrial Temperature Range Available
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Specifications
| Category |
Integrated Circuits (ICs) |
| Family |
Clock/Timing - Real Time Clocks |
| Type |
Clock/Calendar |
| Features |
Alarm, Daylight Savings, Leap Year, NVSRAM, Square Wave Output |
| Memory Size |
113 Bytes |
| Time Format |
HH:MM:SS (12/24 hr) |
| Date Format |
YY-MM-DD-dd |
| Interface |
Parallel |
| Voltage - Supply |
4.5 V ~ 5.5 V |
| Voltage - Supply, Battery |
2.5 V ~ 4 V |
| Operating Temperature |
0°C ~ 70°C |
| Mounting Type |
Through Hole |
| Package / Case |
24-DIP Module (0.600", 15.24mm) |
| Supplier Device Package |
24-EDIP |
| Packaging |
Tube |
| Standard Package |
14 |
Applications/Uses
Embedded Systems
Network Hubs, Bridges, and Routers Security Systems
Utility Meters
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