General Description

The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (hereafter referred to as the DS17x85) provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed NV SRAM.

特性 Features

? Incorporates Industry-Standard DS12887 PC Clock Plus Enhanced Functions

? RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Through 2099

? Optional +3.0V or +5.0V Operation

? SMI Recovery Stack

? 64-Bit Silicon Serial Number

? Power-Control Circuitry Supports System PowerOn from Date/Time Alarm or Key Closure

? Crystal Select Bit Allows Operation with 6pF or 12.5pF Crystal

? 12-Hour or 24-Hour Clock with AM and PM in 12-Hour Mode

? 114 Bytes of General-Purpose, Battery-Backed NV SRAM

? Extended Battery-Backed NV SRAM

??? 2048 Bytes (DS17285/DS17287)

??? 4096 Bytes (DS17485/DS17487)

??? 8192 Bytes (DS17885/DS17887)

? RAM Clear Function

? Interrupt Output with Six Independently Maskable Interrupt Flags

? Time-of-Day Alarm Once per Second to Once per Day

? End of Clock Update Cycle Flag

? Programmable Square-Wave Output

? Automatic Power-Fail Detect and Switch Circuitry

? Available in PDIP, SO, or TSOP Package (DS17285, DS17485, DS17885)

? Optional Encapsulated DIP (EDIP) Package with Integrated Crystal and Battery (DS17287, DS17487, DS17887)

? Optional Industrial Temperature Range Available

? Underwriters Laboratory (UL) Recognized

Applications

??? Embedded Systems

??? Utility Meters

??? Security Systems

??? Network Hubs, Bridges, and Routers