Trigger - Matrox Orion Installation And Hardware Reference

38 Chapter 5: Matrox Orion hardware reference
Direct TTL trigger
Caution
Opto-coupled trigger

Trigger

Matrox Orion accepts an external trigger input which allows
image acquisition to be synchronized to external events
(MIL-Lite MdigControl()). The trigger initiates the capture of
the next valid frame or field.
Trigger signals can be received directly (pin 20 on the expanded
video I/O connector) in TTL format. The amplitude of the TTL
level signal must not exceed 5 V. A signal over 2 V is considered
high, while anything less than 0.8 V is considered low. The
transition of 0.8 V to 2 V is considered to be the rising edge.
The trigger signal's pulse width must be greater than one pixel.
The pulse width is determined by the following:
Minimum pulse width
For example, if the pixel frequency is 24.54 MHz, the minimum
pulse width is 1/24.54 MHz x 2
minimum pulse width must be greater than or equal to 82 nsec.
The direct TTL trigger input is not protected or conditioned.
Use it with caution.
Trigger signals connected to the OPTOTRIG+ (pin 35) and
OPTOTRIG- (pin 34) input pins, pass through an opto-coupler,
a device that protects the board from outside surges. The
voltage difference across OPTOTRIG+ and OPTOTRIG- must
be between 4.05 V and 9.16 V for high level voltage, and
between -5.0 V and 0.8 V for low level voltage.
1
= ------------------------------------------------------ -
pixel frequency (MHz)
≈
82 nsec. Therefore, the
×
2