DS1287 Просмотр технического описания (PDF) - Dallas Semiconductor -> Maxim Integrated
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DS1287 Datasheet PDF : 1 Pages
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DS1287
DS1287
Real Time Clock
FEATURES
• Drop-in replacement for IBM AT computer clock/ca-
lendar
• Pin compatible with the MC146818A
• Totally nonvolatile with over 10 years of operation in
the absence of power
• Self-contained subsystem includes lithium, quartz,
and support circuitry
• Counts seconds, minutes, hours, day of the week,
date, month, and year with leap year compensation
• Binary or BCD representation of time, calendar, and
alarm
• 12- or 24-hour clock with AM and PM in 12-hour mode
• Daylight Savings Time option
• Selectable between Motorola and Intel bus timing
• Multiplex bus for pin efficiency
• Interfaced with software as 64 RAM locations
– 14 bytes of clock and control registers
– 50 bytes of general purpose RAM
• Programmable square wave output signal
• Bus-compatible interrupt signals (IRQ)
• Three interrupts are separately software-maskable
and testable
– Time-of-day alarm once/second to once/day
– Periodic rates from 122 µs to 500 ms
– End of clock update cycle
PIN ASSIGNMENT
MOT 1
NC 2
NC 3
AD0 4
AD1 5
AD2 6
AD3 7
AD4 8
AD5 9
AD6 10
AD7 11
GND 12
24 VCC
23 SQW
22 NC
21 NC
20 NC
19 IRQ
18 RESET
17 DS
16 NC
15 R/W
14 AS
13 CS
24 PIN ENCAPSULATED PACKAGE
PIN DESCRIPTION
AD0–AD7
NC
MOT
CS
AS
R/W
DS
RESET
IRQ
drain)
SQW
VCC
GND
- Multiplexed address/data bus
- No connection
- Bus type selection
- Chip select
- Address strobe
- Read/write input
- Data strobe
- Reset input
- Interrupt request output (open
- Square wave output
- +5 volt supply
- Ground
DESCRIPTION
The DS1287 Real Time Clock is designed to be a direct
replacement for the MC146818A. For a complete
description of operating conditions, electrical and
mechanical characteristics, bus timing, and pin descrip-
tions see the DS12887 data sheet.
050898 1/1
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