CS82C55A96 Intersil, CS82C55A96 Datasheet - Page 5

• Manufacturer Part Number: CS82C55A96
• Description: IC I/O EXPANDER 24B 44PLCC
• Manufacturer: Intersil

Specifications of CS82C55A96

• Interface: Programmable
• Number Of I /o: 24
• Interrupt Output: No
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Frequency - Clock: -

two 4-bit ports under the mode control. Each 4-bit port
contains a 4-bit latch and it can be used for the control signal
output and status signal inputs in conjunction with ports A
and B. See Figure 2B.
Operational Description
Mode Selection
There are three basic modes of operation than can be
selected by the system software:
When the reset input goes “high”, all ports will be set to the
input mode with all 24 port lines held at a logic “one” level by
internal bus hold devices. After the reset is removed, the
82C55A can remain in the input mode with no additional
initialization required. This eliminates the need to pull-up or
pull-down resistors in all-CMOS designs. The control word
register will contain 9Bh. During the execution of the system
program, any of the other modes may be selected using a
single output instruction. This allows a single 82C55A to
service a variety of peripheral devices with a simple software
maintenance routine. Any port programmed as an output
port is initialized to all zeros when the control word is written.
(LATCHED)
(LATCHED)
INTERNAL
INTERNAL
DATA OUT
INTERNAL
INTERNAL
DATA OUT
OR MODE
OR MODE
CHANGE
Mode 0 - Basic Input/Output
Mode 1 - Strobed Input/Output
Mode 2 - Bidirectional Bus
FIGURE 2B. PORT B AND C BUS-HOLD CONFIGURATION
MASTER
CHANGE
DATA IN
DATA IN
RESET
RESET
FIGURE 2A. PORT A BUS-HOLD CONFIGURATION
FIGURE 2. BUS-HOLD CONFIGURATION
OUTPUT MODE
OUTPUT MODE
INPUT MODE
5
V
P
CC
EXTERNAL
PORT A PIN
EXTERNAL
PORT B, C
PIN
82C55A
FIGURE 3. BASIC MODE DEFINITIONS AND BUS INTERFACE
MODE 0
MODE 1
MODE 2
D7 D6 D5 D4 D3 D2 D1 D0
CONTROL WORD
PB7-PB0
PB7-PB0
PB7-PB0
FIGURE 4. MODE DEFINITION FORMAT
RD, WR
B
8
B
8
B
8
I/O
I/O
I/O
PC3-PC0
CONTROL
OR I/O
CONTROL BUS
ADDRESS BUS
4
DATA BUS
82C55A
D7-D0
CONTROL
I/O
C
C
C
CONTROL
PC7-PC4
OR I/O
4
I/O
PORT C (LOWER)
1 = INPUT
0 = OUTPUT
PORT B
1 = INPUT
0 = OUTPUT
MODE SELECTION
0 = MODE 0
1 = MODE 1
PORT C (UPPER)
1 = INPUT
0 = OUTPUT
PORT A
1 = INPUT
0 = OUTPUT
MODE SELECTION
00 = MODE 0
01 = MODE 1
1X = MODE 2
MODE SET FLAG
1 = ACTIVE
PA7-PA0
PA7-PA0
PA7-PA0
A0-A1
CS
A
8
A
8
A
GROUP B
GROUP A
November 16, 2006
I/O
I/O
BI-
DIRECTIONAL
FN2969.10