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V ...... PIO PORT PROCEDURES
The two parallel I/O ports available on
the MIO are both addressed with the same
I/O address from the 8080.
multiplexed using bit 7 of the Control
Output word as discussed in Section III.
The two ports operate identically and have
identical external interfaces on J2 and J3.
The two PIO Ports are used in conjunction
with the Control Port, which in this case
allows the User to read selected Status
Signals from either or both ports.
The PIO Output Ports each contain eight
output data lines and three control lines.
The PIO Input Ports each contain 8 input
data lines and two control lines.
Setting up the PIO Port involves:
1. confuguring the hardware jumpers;
2. making the external interface
3. running test programs to check out
V . l --- HARDWARE JUMPERS
INPUT JUMPER AREA
In the INPUT JUMPER AREA:
The PIO status signals (C3 - C l ) must
be jumpered to the desired input
bits of the Control Port (Row A ) .
PIO STATUS SIGNALS
IDA - Input Data Accepted (as
ODR - Output Data Ready (as
24
connections; and
the operation of the port.
defined in J ' lO External
Interface Connections)
defined in PIO external
Interface Connections)
MIO
User Guide
The ports are
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