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DIO PORT C DATA
BADR3 + 6
PORT C may be configured as an 8-bit port of either input or output, or it may be split into two independent 4-bit ports of
input or output. When split into two 4-bit I/O ports,
D[3:0]
make up the lower nibble,
D[7:4]
comprise the upper nibble. Although it may be split, every
write to Port C is a byte operation. Unwanted information must be ANDed out during reads
and writes must be ORd with current value of the other 4-bit port.
READ/WRITE
D0D1D2D3D4D5D6D7
01324567
DIO CONTROL REGISTER
BADR3 + 7
The DIO Control register is used configure Ports A,B and C as inputs or outputs. Operation is identical to that of the 8255
in Mode 0.
WRITE
D0D1D2D3D4D5D6D7
01324567
The following table summarizes the possible I/O Port configurations for the PCI-DAS1000
DIO operatin in MODE 0:
ININININ1111
OUTINININ0111
INOUTININ1011
OUTOUTININ0011
ININOUTIN1101
OUTINOUTIN0101
INOUTOUTIN1001
OUTOUTOUTIN0001
INININOUT1110
OUTININOUT0110
INOUTINOUT1010
OUTOUTINOUT 0010
ININOUTOUT1100
OUTINOUTOUT0100
INOUTOUTOUT1000
OUTOUTOUTOUT0000
PORT C
LOWER
PORT BPORT C
UPPER
PORT AD0D1D3D4
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