K25C81-FB Datasheet, PDF (1/12 Pages) Semtech Corporation – Versatile PC/XC/AT/PS/2 Compatible Keyboard Encoder

FlexiCoder^TM K25C81
Versatile PC/XC/AT/PS/2 Compatible
Keyboard Encoder
HID & SYSTEM MANAGEMENT PRODUCTS, KEYCODER^TM FAMILY
DESCRIPTION
The FlexiCoder^TM is a versatile, low-
power keyboard encoder. It offers
two bi-directional channels for
communicating with a
PC/XT/AT/PS2 system, and/or any
optional keyboard-compatible
devices, such as an 83 or 101/102
standard desktop keyboard, OCR,
barcode reader, etc. The K25C81
directly interfaces a PC keyboard
port, making custom keyboard to
system communications fully
transparent.
On an 8 x 18 matrix, the
FlexiCoder^TM will scan, debounce
and encode up to 144 keys. Scan
codes corresponding to single keys
of the IBM 101 keyboard, or a
combination of these keys when
depressed with Shift, Ctrl, and Alt
keys, are generated with each key
press. Custom keypad input is not
effected by the Shift States of an
external keyboard.
Users can conveniently define key
assignments on the matrix as single
or repeating actions. All keys must
be released between key strokes or
scanning is suspended. The
encoder can buffer up to 122
keycodes, and control inputs and
outputs are provided for interfacing
with contact keyboards.
The FlexiCoder^TM is ideal for use
with either BIOS-compatible chip
sets or single-board computers for
PC systems requiring a custom
keyboard / keypad as an alternate
or additional input device. Boards
and evaluation kits are immediately
obtainable and ready to connect.
FEATURES
• Directly interfaces a PC
keyboard port
• Encodes up to 144 custom keys
on an 8 X 18 matrix
• Buffers up to 122 keycodes
• Interfaces to 83/101/102
standard keyboard or other
8042-compatible device
APPLICATIONS
• Custom keyboards/keypads
• Control panels
• Automatic teller machines
• Embedded control systems
• Public Information Kiosks
PIN ASSIGNMENTS
• Enables custom keypad scan
codes to remain unaffected by
the Shift States of an external
keyboard
• Includes jumper-selectable auto-
repeat for designated keys
• Offers two-key inhibit scanning
mode
• Instrumentation
• Test and Measurement equipment
• Point of Sales terminals
• Industrial Controllers
• Medical Instruments
_RESET 1
40 Vcc
_IRQ 2
39 OSCI
VX 3
38 OSCO
C17 4
37 EKC1
R6 5
36 R7
RP 6
35 NC
KD 7
KC 8
34 R5
33 R4
6
RP 7
KD
40
1
1
39 R7
R6
NC
RP
NC
R5
EKC 9
EKD 10
C16 11
C0 12
DIP
32 R3
31 R2
30 R1
29 R0
KC
EKC
EKD
C16 12
C0
C1
C2
PLCC
R5
R4
R3
34 R2
R1
R0
C8
KD
KC
EKC
EKD
C16
C0
R4
R3
R2
QFP
R1
R0
C8
C1 13
28 C8
C3
C4 17
C9
C1
29 C10
C2
C9
C10
C2 14
27 C9
18
23
28
C3
C11
C3 15
26 C10
C4 16
25 C11
C5 17
24 C12
C6 18
23 C13
C7 19
22 C14
Vss 20
21 C15
FlexiCoder^TM is a trademark of Semtech Corp. All
other trademarks belong to their respective
companies.
Copyright Semtech, 1997-2001
1
DOC5-C81-DS-105
www.semtech.com