HS-82C55ARH(1995) Ver la hoja de datos (PDF) - Intersil
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HS-82C55ARH Datasheet PDF : 23 Pages
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Pin Description
SYMBOL
PA0-7
PIN
NUMBERS
1-4, 37-40
PB0-7
PC0-3
PC4-7
D0-7
18-25
14-17
10-13
27-34
VDD
26
GND
7
CS
6
RD
5
WR
36
A0 and A1
8, 9
Reset
35
HS-82C55ARH
TYPE
I/O
I/O
I/O
I/O
I/O
I
I
I
I
I
I
I
DESCRIPTION
Port A: General purpose I/O Port. Data direction and mode is determined by the contents
of the Control Word.
Port B: General purpose I/O port. See Port A.
Port C (Lower): Combination I/O port and control port associated with Port B. See Port A.
Port C (Upper): Combination I/O Port and control port associated with Port A. See Port A.
Bidirectional Data Bus: Three-State data bus enabled as an input when CS and WR are
low and as an output when CS and RD are low.
VDD: The +5V power supply pin. A 0.1µF capacitor between pins 26 and 7 is recommend-
ed for decoupling.
Ground.
Chip Select: A “low” on this input pin enables the communication between the
HS-82C55ARH and the CPU.
Read: A “low” on this input pin enables the HS-82C55ARH to send the data or status
information to the CPU on the data bus. In essence, it allows the CPU to “read from” the
HS-82C55ARH.
Write: A “low” on this input pin enables the CPU to write data or control words into the
HS-82C55ARH.
Port Select 0 and Port Select 1: These input signals, in conjunction with the RD and WR
inputs, control the selection of one of the three ports or the control word registers. They are
normally connected to the Least Significant Bits of the address bus (A0 and A1).
Reset: A “high” on this input clears the control register and all ports (A, B, C) are set to the
input mode. “Bus hold” devices internal to the HS-82C55ARH will hold the I/O port inputs
to a logic “1” state with a maximum hold current of 400µA.
Functional Diagram
POWER
SUPPLIES
+5V
GND
GROUP A
CONTROL
GROUP A
PORT A
(8)
I/O
PA7 - PA0
BIDIRECTIONAL
DATA BUS
D7 - D0
DATA
BUS
BUFFER
RD
WR
A1
A0
RESET
CS
READ/WRITE
CONTROL
LOGIC
8-BIT INTERNAL
DATA BUS
GROUP B
CONTROL
971
GROUP A
PORT C
UPPER (4)
GROUP B
PORT C
LOWER (4)
I/O
PC7 - PC4
I/O
PC3 - PC0
GROUP B
PORT B
(8)
I/O
PB7 - PB0
Spec Number 518060
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