LS7223_03 Datasheet, PDF (1/4 Pages) LSI Computer Systems – KEYPAD PROGRAMMABLE DIGITAL LOCK

LSI/CSI
LS7223
U_{® L} ^{LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 [phone] FAX [phone]}
A3800
KEYPAD PROGRAMMABLE DIGITAL LOCK
January 2003
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 (VDD - VSS)
• LS7223 (DIP); LS7223-S (SOIC) - See Figure 1
CONNECTION DIAGRAM - TOP VIEW
V SS (-V) 1
RC-OSC 2
X1 3
X2 4
X3 5
X4 6
20 _{VDD (+V)}
19 CAP-K
18 LOCK DISPLAY
17 LOCK 1
16 LOCK 2
15 ALARM
GENERAL DESCRIPTION:
The LS7223 is a programmable electronic lock implemented
in a CMOS integrated circuit. The circuit contains all the nec-
essary memory, decoder and control logic to make a pro-
grammable "keyless" lock system to control electro-
mechanical locks. Input is provided by a matrix keypad whose
maximum allowable size is 4 x 4.
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
is done via the keypad inputs. Any entry from the keypad
(when not in the program mode) which does not match one of
the 3 programmed codes causes the Tamper output to
become active.
The low power CMOS design of the LS7223 enables it to be
designed into battery backed-up and automotive type security
systems.
DETAILED DESCRIPTION:
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
the keypad entry enable time expires. The 3 codes and their
functions are explained below.
1. The Primary code, when entered from the keypad, causes
the Lock 1 output to toggle and the Momentary output to
momentarily go high. Whenever power is first applied to
the LS7223, the circuit defaults to the Primary code
corresponding to the keys X1Y1, X1Y2, X2Y2, X2Y1. The
code can then be altered to any other 4 digit code by en-
tering the Program mode and keying in the new code.
Y1 7
Y2 8
Y3 9
Y4 10
FIGURE 1
14 MOM
13 TAMPER
12 CAP-M
11 PROGRAM
2. The Secondary code, when entered from the key-
pad, causes the Lock 2 output to toggle. The first 3
digits of the Secondary code must be identical to the
first 3 digits of the Primary code; the 4th digit may or
may not be identical for the two codes. When the
two codes are the same in all 4 digits, the entry of
the code will cause both the Lock 1 and the Lock 2
outputs to toggle. Whenever power is first applied
to the LS7223, the circuit defaults to the Secondary
code corresponding to the keys X1Y1, X1Y2, X2Y2,
X1Y1. The code can then be altered by entering the
Program mode.
3. The Duress code, when entered from the keypad,
causes the Lock 1 output to toggle; at the same time
the Alarm output will latch high to enable an external
alarm. The first 3 digits of the Duress code must be
identical to the first 3 digits of the Primary and
Secondary codes; the 4th digit must be different to
activate the Alarm output. Whenever power is first
applied to the LS7223, the circuit defaults to the
Duress code corresponding to the keys X1Y1,
X1Y2, X2Y2, X1Y2. The code can then be altered
the same way as the other two codes.
7223-012703-1