Impulse PIO-48.PC104 (3701) User Manual
Page 15
© Sealevel Systems, Inc.
- 13 -
PIO-48.PC104 User Manual
I/O Control Word
Each port may be configured as either Input or Output. This is accomplished by
writing the correct Control Word (CW) to the proper register.
CWnD0
Port C1 lower nibble (bits 0-3)
1 = input
0 = output
1 on power up
CWnD1
Port B1
1 = input
0 = output
1 on power up
CWnD2
0 or 1 (no effect)
CWnD3
Port C1 upper nibble (bits 4-7)
1 = input
0 = output
1 on power up
CWnD4
Port A1
1 = input
0 = output
1 on power up
CWnD5
0 or 1 (no effect)
CWnD6
0 or 1 (no effect)
CWnD7
0 or 1 (no effect)
Control Word (X = 0)
Hex Value
Port Setup
7 6 5 4 3 2 1 0
A
B
C Upper
C Lower
X X X 0 0 X 0 0
80
Out Out
Out
Out
X X X 0 0 X 0 1
81
Out Out
Out
In
X X X 0 0 X 1 0
82
Out In
Out
Out
X X X 0 0 X 1 1
83
Out In
Out
In
X X X 0 1 X 0 0
88
Out Out
In
Out
X X X 0 1 X 0 1
89
Out Out
In
In
X X X 0 1 X 1 0
8A
Out In
In
Out
X X X 0 1 X 1 1
8B
Out In
In
In
X X X 1 0 X 0 0
90
In Out
Out
Out
X X X 1 0 X 0 1
91
In Out
Out
In
X X X 1 0 X 1 0
92
In In
Out
Out
X X X 1 0 X 1 1
93
In In
Out
In
X X X 1 1 X 0 0
98
In Out
In
Out
X X X 1 1 X 0 1
99
In Out
In
In
X X X 1 1 X 1 0
9A
In In
In
Out
X X X 1 1 X 1 1
9B
In In
In
In