Chapter 3
Hardware Overview
3-6
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Acquisition Window Control
You can configure numerous parameters on the 1408 device to control the
video acquisition window. A brief description of each parameter follows:
•
Horizontal sync—HSYNC is the synchronization pulse signal
produced at the beginning of each video scan line that keeps a video
monitor’s horizontal scan rate in sequence with the transmission of
each new line.
•
Vertical sync—VSYNC is the synchronization pulse generated at the
beginning of each video field that signals the video monitor when to
start a new field.
•
Pixel clock—PCLK times the sampling of pixels on a video line.
•
Composite sync—CSYNC is the signal consisting of combined
horizontal sync pulses and vertical sync pulses.
•
Active pixel region—The active pixel region is the region of pixels
actively being stored. The active pixel region is defined by a pixel start
(relative to HSYNC) and a pixel count.
•
Horizontal count—The horizontal count is the total number of pixels
between two HSYNC signals. The horizontal count determines the
frequency of the pixel clock.
•
Active line region—The active line region is the region of lines
actively being stored. The active line region is defined by a line start
(relative to VSYNC) and a line count.
•
Line count—The line count is the total number of horizontal lines in
the picture.
•
Video line—A video line consists of an HSYNC, back porch, active
pixel region, and a front porch, as shown in Figure 3-2.
Figure 3-2.
Video Line
Horizontal Sync
Pixel Region
Back Porch
Front Porch
