Data Translation MACH Series, User Manual

Page: 36 / 214

Chapter 2
20
External Pixel Clock
For area-scan operations, pin 1 (EXT_CLK) of connector J1 on the
DT3152-LS board is provided for connecting an external pixel clock.
The frequency of the external pixel clock can range between 0 and
20 MHz (200 mV peak-to-peak).
For line-scan operations, pin 12 (MCLK_IN
−
) and pin 11
(MCLK_IN
+)
of the J2 connector are provided for connecting the
RS-422, master clock input signals from the video source.
External Trigger
The DT3152-LS frame grabber board provides pin 3 (EXT_TRIGGER)
on connector J1 for connecting an external trigger input.
Using an external trigger, you can synchronize an acquisition with an
external event. In line-scan mode only, you can also use an external
trigger to perform a continuous-acquire passthru operation
(described on
page 48 ).
By default, the external trigger is disabled. Through software, you
can enable the external trigger and specify whether you want
acquisition to start on a low-to-high (rising-edge) transition or a
high-to-low (falling-edge) transition on pin 3 of connector J1.