
Crystal Vision
General Purpose Interface
4 General Purpose Interface
Introduction
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.
ViViD 3G has four GPI inputs and two GPI outputs.
Each General Purpose Interface (GPI) input is fitted with a
6800Ω resistor connected to the
in5V and in the following table, this equates to logic ‘H’. With the GPI preset recall
lines set to ‘level’ mode and no connections (logic ‘HHHH’), preset 1 will be selected. With the
GPI preset recall lines set to ‘pulse’ mode, the GPI will be activated whenever a bit is pulled
low but no change to the preset selection will occur when all bits return to logic ‘HHHH’. Note
that preset 16 is not accessible in pulse mode.
Note: Because the GPI inputs are sampled in the vertical interval it is recommended that in
‘pulse’ mode, the GPI should be asserted at least 2mS before the start of vertical sync to
ensure stability and held active for at least 40mS.
See
in this manual for details of inverting the GPI preset logic.
Each General Purpose Interface (GPI) output
has a 270Ω resistor in series with its output.
This allows for an external LED to be driven, connected to a DC voltage of +5V.
The GPI inputs can be programmed to automatically recall a previously saved preset
configuration. The 16 user preset configurations are selected using binary notation.The two
outputs can be programmed to assert themselves for a number of different alarm conditions.
GPI
Low (<1V)
High (+5V)
1
‘a’
Recall preset bit 1
See following table for user preset control
2
‘b’
Recall preset bit 2
3
‘c’
Recall preset bit 4
4
‘d’
Recall preset bit 8
5
‘e’
Alarms
(See alarm table)
Alarm condition
No alarm
6
‘f’
Alarms (
See alarm table)
Alarm condition
No alarm
Table showing the six GPI functions
GPI
Bit 8
Bit 4
Bit 2
Bit 1
Preset
1
H
H
H
H
2
H
H
H
L
3
H
H
L
H
4
H
H
L
L
5
H
L
H
H
6
H
L
H
L
ViViD 3G User Manual R1.4
12
19 January 2021