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參數資料
| 型號： | K25C81-FB |
| 廠商： | Semtech Corporation |
| 英文描述： | Versatile PC/XC/AT/PS/2 Compatible Keyboard Encoder |
| 中文描述： | 多功能PC/XC/AT/PS/2兼容鍵盤編碼器 |
| 文件頁數： | 3/12頁 |
| 文件大?。?/td> | 124K |
| 代理商： | K25C81-FB |
FUNCTIONAL DESCRIPTION
PIN DEFINITIONS
Copyright Semtech, 1997-2001
DOC5-C81-DS-105
www.semtech.com
3
Mnemonic
Vcc
Vss
OSCI
OSCO
_RESET
DIP
40
20
39
38
1
PLCC
44
22
43
42
1
QFP
38
17
37
36
41
T Y PE
I
I
I
O
I
Name and Func tion
Power S upply:
+5V
Ground
Osc ilator Input
Osc ilator Output
Reset:
apply 0 V to provide orderly
start-up.
Must be tied to Vcc
Tie to Vcc.
Rollover Mode S elec tion:
tie to
Vcc to select N-Key Rollover. Tie to
Ground to select Two-Key Inhibit
Mode.
K eyboard Cloc k:
connects to PC’s
keyboard port Clock Line.
K eyboard Data:
connects to PC’s
keyboard port Data Line.
External K eyboard Data:
connects to external keyboard Data
Line.
External K eyboard Cloc k:
connects to external keyboard Clock
Line.
External K eyboard Cloc k 2:
connects to external keyboard Clock
Line and is used to generate an
interrupt for every Clock Line transition.
This signal must be inverted for PC/XT
keyboards.
Column S elec t Outputs:
select
one of columns.
_IRQ
VX
RP
2
3
6
2
4
7
42
43
2
I
I
I
KC
8
9
4
I/O
KD
7
8
3
I/O
EKD
10
11
6
I/O
EKC
9
10
5
I/O
EKC1
37
41
35
I
C0-C7
12-19
3-17
18
19-21
31-24
12
5
8-15
O
C8-C15
C16
C17
28-21
11
4
26-18
7
44
O
I/O
K eyboard type selec tion:
this pin
is used both as outputs for column
select and as input for standard
keyboard-type selection.
Row data inputs
R0-R5
R6
R7
NC
29-34
5
36
35
32-37
6
39
38, 3
18, 23
40
27-32
1
34
16, 33
22, 39
40
I
I
I
-
-
No Connec ts:
these pins are
unused.
Note:
An underscore before a pin mnemonic denotes an active low signal.
The FlexiCoder
TM
consists of six
major sections (see functional
diagram, previous page). These
are the Keyboard Encoder, the
Mode Control Unit, the PC
Communication Channel, the 8042
Emulation Channel, the Interrupt
Control Unit and the Data Buffer.
These sections communicate with
each other and operate
concurrently.
The controller continuously scans a
keyboard organized as an 8 row by
18 column matrix, for a maximum of
144 keys. Smaller-size keyboards
can be connected provided that all
unused row pins are connected to
Vcc. The microcontroller selects
one of the 18 column lines (C0-C17)
every 512 μS and then reads the
row data lines (R0-R7).
A key closure is detected as a zero
in the corresponding position of the
matrix. A complete scan cycle for
the entire keyboard takes approxi-
mately 9.2 mS. Each key press is
debounced for a period of 20 mS.
Once the key is verified, the
corresponding key code(s) are
loaded into the transmit buffer of
the PC Keyboard Communication
Channel.
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相關代理商/技術參數 |
參數描述 |
|---|---|
| K25C81-FN | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:Versatile PC/XC/AT/PS/2 Compatible Keyboard Encoder |
| K25C81-P | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:Versatile PC/XC/AT/PS/2 Compatible Keyboard Encoder |
| K25F | 制造商:VMI 制造商全稱:VMI 功能描述:2,500 V - 10,000 V Rectifiers 1.5 A - 3.0 A Forward Current 200 ns Recovery Time |
| K25S | 制造商:VMI 制造商全稱:VMI 功能描述:Spice Model |
| K25UF | 制造商:VMI 制造商全稱:VMI 功能描述:Spice Model |
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