Crystal Vision
Hardware installation
11
26/01/06
2.2 General Purpose Interface (GPI)
Each frame slot has up to six connections ‘a-f ‘for GPI control and monitoring. These
connections are available at the rear of the frame on the 26-way D type Remote
connectors.
GPI
Low (<1V)
High (+5V)
0
‘a’
Recall preset bit 1
No user connection at present
1
‘b’
Recall preset bit 2
No user connection at present
2
‘c’
Recall preset bit4
No user connection at present
3
‘d’
Recall preset bit 8
No user connection at present
4
‘e’
Audio follow pulse
Pulse width equal to audio delay
5
‘f’
loss of
input/ref/frozen
No user connection at present
As supplied, each GPI output has a 220
Ω
resistor in series with its output. This allows for
an external LED to be driven, connected to a DC voltage of +5V.
The 16 user preset configurations can be recalled using binary notation.
GPI
Bit 4
Bit 3
Bit 2
Bit 1
Preset
0
0
0
0
0
1
0
0
0
1
2
0
0
1
0
3
0
0
1
1
4
0
1
0
0
5
0
1
0
1
6
0
1
1
0
7
0
1
1
1
8
1
0
0
0
9
1
0
0
1
10
1
0
1
0
11
1
0
1
1
12
1
1
0
0
13
1
1
0
1
14
1
1
1
0
15
1
1
1
1
