DS1215
DS1215
Phantom Time Chip
FEATURES
PIN ASSIGNMENT
X1
X2
WE
BAT1
GND
D
Q
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CCI
V
CCO
BAT2
RST
OE
CEI
CEO
ROM/RAM
•
Keeps track of hundredths of seconds, seconds, min-
utes, hours, days, date of the month, months, and
years
•
Adjusts for months with fewer than 31 days
•
Leap year automatically corrected up to 2100
•
No address space required
•
Provides
nonvolatile controller functions for battery
backup of RAM
redundant batteries for high–reliability
applications
16–PIN DIP (300 MIL)
X1
X2
WE
BAT1
GND
D
Q
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CCI
V
CCO
BAT2
RST
OE
CEI
CEO
ROM/RAM
•
Supports
•
Uses a 32.768 KHz watch crystal
•
Full
±10%
operating range
•
Operating temperature range 0°C to 70°C
•
Space-saving, 16–pin DIP package and SOIC
•
Optional industrial temperature range –40°C to +85°C
(IND)
16–PIN SOIC (300 MIL)
PIN DESCRIPTION
X1, X2
– 32.768 KHz Crystal Connections
WE
– Write Enable
BAT1
– Battery 1 Input
GND
– Ground
D
– Data In
Q
– Data Out
– ROM/RAM Select
ROM/RAM
– Chip Enable Out
CEO
CEI
– Chip Enable Input
OE
– Output Enable
RST
– Reset
BAT2
– Battery 2 Input
– Switched Supply Output
V
CCO
– +5 VDC Input
V
CCI
NOTE: Both pins 5 and 8 must be grounded.
DESCRIPTION
The DS1215 Phantom Time Chip is a combination of a
CMOS timekeeper and a nonvolatile memory controller.
In the absence of power, an external battery maintains
the timekeeping operation and provides power for a
CMOS static RAM. The watch keeps track of hun-
dredths of seconds, seconds, minutes, hours, day, date,
month, and year information. The last day of the month
is automatically adjusted for months with less than 31
days, including correction for leap year every four years.
The watch operates in one of two formats: a 12–hour
mode with an AM/PM indicator or a 24–hour mode. The
nonvolatile controller supplies all the necessary support
circuitry to convert a CMOS RAM to a nonvolatile
memory. The DS1215 can be interfaced with either
RAM or ROM without leaving gaps in memory.
ORDERING INFORMATION
DS1215
DS1215S
DS1215N
DS1215SN
16–pin DIP
16–pin SOIC
16–pin DIP (IND)
16–pin SOIC (IND)
ECopyright
1997 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor data books.
032697 1/15
DALLAS [ DALLAS SEMICONDUCTOR ]
