LSI/CSI
UL
®
LS7223
(631) 271-0400 FAX (631) 271-0405
December 2002
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
A3800
KEYPAD PROGRAMMABLE DIGITAL LOCK
FEATURES
:
• Stand alone lock logic
• 38416, 4-digit combinations
• 3 different user programmable codes
• Momentary and static lock control outputs
• Internal key debounce circuit
• Tamper detection output
• Status outputs
• Low current consumption
• +4V to +15V operation (V
DD
-V
SS
)
• LS7223 (DIP), LS7223-S (SOIC) - See Figure 1
GENERAL DESCRIPTION:
The LS7223 is a programmable electronic lock implemented
in a monolithic CMOS integrated circuit. The circuit contains
all the necessary memory, decoder and control logic to make
a programmable "keyless" lock system to control electro-
mechanical locks. Input is provided by a matrix keypad whose
maximum allowable size is 4 x 4.
CONNECTION DIAGRAM -
TOP VIEW
V
SS
(-V)
RC-OSC
X1
X2
X3
X4
Y1
Y2
Y3
Y4
1
2
3
4
20
V
DD
(+V)
19
CAP-K
18
LOCK DISPLAY
17
LOCK 1
LSI
LS7223
5
6
7
8
9
10
16
LOCK 2
15
ALARM
14
MOM
13
12
TAMPER
CAP-M
11
PROGRAM
FIGURE 1
The LS7223 can be programmed to recognize 3 different
codes: one to toggle an output and generate a pulse
(Primary), one to toggle an output (Secondary), and one to
toggle an output and trigger an alarm (Duress). Programming 2. The Secondary code, when entered from the key-
pad, causes the Lock 2 output to toggle. The first 3
is done via the keypad inputs. Any entry from the keypad
digits of the Secondary code must be identical to the
(when not in the program mode) which does not match one of
first 3 digits of the Primary code; the 4th digit may or
the 3 programmed codes causes the Tamper output to
may not be identical for the two codes. When the
become active.
two codes are the same in all 4 digits, the entry of
the code will cause both the Lock 1 and the Lock 2
The monolithic, low power CMOS design of the LS7223
outputs to toggle. Whenever power is first applied
enables it to be designed into typical battery backed-up and
to the LS7223, the circuit defaults to the Secondary
automotive type security systems.
code corresponding to the keys X1 Y1, X1 Y2, X2
Y2, X1 Y1. The code can then be altered by
DETAILED DESCRIPTION:
entering the Program mode.
CODES - There are 3 different function codes which the
LS7223 can store in memory. Each code consists of a 4 digit
number which must be entered in exact sequence and before 3. The Duress code, when entered from the keypad,
causes the Lock 1 output to toggle; at the same time
the keypad entry enable time expires. The 3 codes and their
the Alarm output will latch high to enable an external
functions are explained below.
alarm. The first 3 digits of the Duress code must be
identical to the first 3 digits of the Primary and
1. The Primary code, when entered from the keypad, causes
Secondary codes; the 4th digit must be different to
the Lock 1 output to toggle and the Momentary output to
activate the Alarm output. Whenever power is first
momentarily go high. Whenever power is first applied to
applied to the LS7223, the circuit defaults to the
the LS7223, the circuit defaults to the Primary code
Duress code corresponding to the keys X1 Y1, X1
corresponding to the keys X1 Y1, X1 Y2, X2 Y2, X2 Y1.
Y2, X2 Y2, X1 Y2. The code can then be altered
The code can then be altered to any other 4 digit code by
the same way as the other two codes.
entering the Program mode and keying in the new code.
7223-121102-1
LSI [ LSI COMPUTER SYSTEMS ]
