DS1284/DS1286
PIN
NAME
FUNCTION
DIP
EDIP
PLCC
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 VCC is below VTP, read and writes are inhibited.
However, the timekeeping function continues unaffected by the
lower input voltage.
28
28
28
VCC
Figure 1. Block Diagram
VCC
VBAT
X1
PF delay
Power
Switch
÷
÷
÷
Oscillator
8
40.96
40.96
÷
10
GND
X2
DS1286 only
DS1286
only
1024Hz
SQW
÷
4
Internal Registers
INTA
External Registers,
clock, calendar,
TD INT
Update seconds through
years and check time of
day alarm
N
Swap
pins
time of day alarm
WD INT
Command
Register
VCC
A0-A5
100Hz
IBH
P
CE
OE
WE
User RAM
50 Bytes
100Hz
INTB
(INTB)
/
Internal Counters
External
Internal Registers
External
N
Registers
Registers
Watchdog Alarm
Internal Counters
Hundredths of
Seconds
DS1284/DS1286
Data I/O Buffers
DQ0–DQ7
4 of 18
DALLAS [ DALLAS SEMICONDUCTOR ]
