msm82c55a-2rs Oki Semiconductor, msm82c55a-2rs Datasheet - Page 9

• Manufacturer Part Number: msm82c55a-2rs
• Description: Cmos Programmable Peripheral Interface
• Manufacturer: Oki Semiconductor

¡ Semiconductor
PIN DESCRIPTION
PB
PA
PC
Pin No.
D
RESET
A
GND
7
WR
7
7
7
V
0
CS
RD
, A
- D
- PA
- PB
- PC
CC
1
0
0
0
0
Port Select Input
Bidirectional
Chip Select
Write Input
Reset Input
(Address)
Read Input
Data Bus
Port B
Port A
Port C
Input
Item
–
–
Input/Output
Input and
Input and
Input and
Input and
Output
Output
Output
Output
Input
Input
Input
Input
Input
–
–
When the CS is in low level, data transmission is enabled with CPU.
When it is in high level, the data bus is made into the high impedance
status where no write nor read operation is performed. Internal
registers hold their previous status, however.
When WR is in low level, data or control words are transferred from
CPU to MSM82C55A-2.
By combination of A
port A, port B, port C, and control register. These pins are usually
connected to low order 2 bits of the address bus.
These are universal 8-bit I/O ports. The direction of inputs/ outputs
can be determined by writing a control word. Especially, port A can
be used as a bidirectional port when it is set to mode 2.
These are universal 8-bit I/O ports. The direction of inputs/outputs
ports can be determined by writing a control word.
+5V power supply.
These are three-state 8-bit bidirectional buses used to write and
read data upon receipt of the WR and RD signals from CPU and also
used when control words and bit set/reset data are transferred from
CPU to MSM82C55A-2.
This signal is used to reset the control register and all internal
registers when it is in high level. At this time, ports are all made into
the input mode (high impedance status).
all port latches are cleared to 0.
and all ports groups are set to mode 0.
When RD is in low level, data is transferred from MSM82C55A-2 to
CPU.
These are universal 8-bit I/O ports. The direction of inputs/outputs
can be determined by writing a control word as 2 ports with 4 bits
each. When port A or port B is used in mode 1 or mode 2 (port A
only), they become control pins. Especially, when port C is used as
an output port, each bit can set/reset independently.
GND
0
and A
1
, either one is selected from among
Function
MSM82C55A-2RS/GS/VJS
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