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
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.
28
28
28
V
CC
Figure 1. Block Diagram
V
CC
X1
X2
DS1286
only
÷
4
Internal Registers
Address Decode and Control
External Registers,
clock, calendar,
time of day alarm
Command
Register
100Hz
User RAM
50 Bytes
Internal Counters
External
Registers
Watchdog Alarm
Internal Counters
100Hz
Internal Registers
External
Registers
Hundredths of
Seconds
Update seconds through
years and check time of
day alarm
TD INT
Swap
pins
WD INT
V
CC
IBH
P
N
V
BAT
Oscillator
÷
8
÷
40.96
÷
40.96
PF delay
÷
10
Power
Switch
GND
DS1286 only
1024Hz
SQW
INTA
A0-A5
CE
OE
WE
INTB/
(INTB)
N
DS1284/DS1286
Data I/O Buffers
DQ0–DQ7
4 of 18
DALLAS [ DALLAS SEMICONDUCTOR ]
