cdp1871ac Intersil Corporation, cdp1871ac Datasheet - Page 2

• Manufacturer Part Number: cdp1871ac
• Description: Cmos Keyboard Encoder
• Manufacturer: Intersil Corporation

CS2
CS3
CS4
TPB
RPT
CS1
DA
CDP1800-SERIES
R
C
X
X
BUS0-BUS7
V
21
22
23
24
34
33
35
DD
CPU
DEBOUNCE
36
R
N0-N2
N
MRD
FIGURE 1. TYPICAL CDP1800 SERIES MICROPROCESSOR SYSTEM USING THE CDP1871A
TPB
CONTROL
LATCHES
DETECT
STATUS
CS
LOGIC
KEY
F/F
8 BIT DATA BUS
V
DD
CONTROL
ALPHA LOCK
CONTROL
NORMAL
SHIFT
SCAN CLOCK
KEY DOWN
DETECT
21
23
24
34
39
38
37
CS1,
CS2,
CS3
CS4
TPB
SHIFT
CONTROL
ALPHA
40
FIGURE 2. CDP1871A BLOCK DIAGRAM
V
12
CDP1871A
BUS0-BUS7
DD
DEBOUNCE
CDP1871A, CDP1871AC
25
SCAN COUNTER
THREE-STAGE
KEY BOARD
R
100K
PD
SENSE
LINES
FROM
32
1 OF 8
MUX
36
0.1 F
D11
D1
S1
S2
S3
S4
S5
S6
S7
S8
19
4-67
12
13
14
15
16
17
18
19
1
11
R
PD
DI
SCAN COUNTER
1
KEY BOARD
FIVE-STAGE
DECODER/
DRIVERS
DRIVE
LINES
OF 8 SWITCHES EACH
TO
II
UP TO 11 SETS
BUS ENABLE
C1-C3
C4-C8
DII
11
ALPHA
37
SHIFT
39
THREE-STATE
BUFFERS
OUTPUT
LATCH
R
PD
CONTROL
38
V
V
DD
SS
R
PD
25
32
40
20
BUS 0
BUS 7