DS1286 Datasheet, PDF (4/18 Pages) Dallas Semiconductor – Watchdog Timekeeper

DS1284/DS1286
DIP
PIN
EDIP PLCC
NAME
FUNCTION
Primary Power-Supply Input. When voltage is applied within
normal limits, the device is fully accessible and data can be
28
28
28
V_CC
written and read. When a backup supply is connected to the
device and V_CC is below V_TP, read and writes are inhibited.
However, the timekeeping function continues unaffected by the
lower input voltage.
Figure 1. Block Diagram
V_CC
X1
Oscillator
8
X2
DS1286
only
 40.96
 40.96
PF delay
 10
Power
Switch
V _BAT
GND
4
DS1286 only
1024Hz
SQW
A0-A5
CE
OE
WE
Internal Registers
External Registers,
clock, calendar,
time of day alarm
Command
Register
User RAM
50 Bytes
Update seconds through
years and check time of
day alarm
TD INT
WD INT
Swap
pins
100Hz
Internal Counters
External
Registers
Watchdog Alarm
Internal Counters
IBH
100Hz
Internal Registers
External
Registers
Hundredths of
Seconds
INTA
N
V _CC
P
N
INTB/
(INTB)
Data I/O Buffers
DQ0–DQ7
DS1284/DS1286
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