Chapter 3 Hardware Overview
© National Instruments Corporation 3-5 IMAQPCI/PXI-1428 User Manual
Start Conditions
The IMAQ 1428 can start acquisitions in the following ways:
• Software control—The IMAQ 1428 supports software control of
acquisition start. You can configure the IMAQ 1428 to capture a fixed
number of frames. This configuration is useful for capturing a single
frame or a sequence of frames.
• Trigger control—You can start an acquisition by enabling external
orRTSI bus trigger lines. Each of these inputs can start a video
acquisition on a rising or falling edge. You can use all four external
triggers and up to four RTSI bus triggers simultaneously.
• Delayed acquisition—Use either software or triggers to start
acquisitions instantaneously or after skipping a specific number of
frames. You can use delayed acquisition for post-trigger applications.
Acquisition Window Control
You can configure the following parameters on the IMAQ 1428 to control
the video acquisition window:
• Acquisition window—The IMAQ 1428 allows the user to specify a
particular region of active pixels and active lines within the incoming
video data. The active pixel region selects the starting pixel and
number of pixels to be acquired relative to the assertion edge of the
horizontal (or line) enable signal from the camera. The active line
region selects the starting line and number of lines to be acquired
relative to the assertion edge of the vertical (or frame) enable signal.
• Region of interest—The IMAQ 1428 uses a second level of active pixel
and active line regions for selecting a region of interest. Using the
region-of-interest circuitry, the device acquires only a selected subset
oft he acquisition window.
Serial Interface
The IMAQ 1428 provides serial connections to and from the camera
through two LVDS pairs in the Camera Link cable. All Camera Link serial
communication uses one start bit, one stop bit, no parity, and no hardware
handshaking.
The IMAQ 1428 supports the following baud rates: 56000, 38400, 19200,
9600, 7200, 4800, 3600, 2400, 2000, 1800, 1200, 600, and 300.