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DCEX
Class
Description
Command syntax
Query syntax
Query response
Other required
commands
Example
882 Video Test Instrument User Guide (Rev A.35)
Display Code EXpected
Format parameter settings
Sets up the display code that is expected from a display connected to the generator. The
code is determined by one or more sense lines being connected to ground by the display.
Many video controller cards for the Apple Macintosh II and VGA type cards for the IBM-PC
sample the status of the display code sense lines. The information then sets up one of
several different operating modes to match a particular display. An improper display code
may make the controller card or display appear to malfunction.
The DCEX? query first performs a logical AND operation with the display code bit mask
and the actual display code that's sensed. The decimal equivalent of the result then is
returned. The mask is set with the DCEX command.
The expected setting and the actual result are both shown in the Format test image. They
have no effect how a given format generates a set of test signals.
DCEX code
code
0 = 0 0 0 0
8 = 1 0 0 0
1 = 0 0 0 1
9 = 1 0 0 1
2 = 0 0 1 0
10 = 1 0 1 0
3 = 0 0 1 1
11 = 1 0 1 1
4 = 0 1 0 0
12 = 1 1 0 0
5 = 0 1 0 1
13 = 1 1 0 1
6 = 0 1 1 0
14 = 1 1 1 0
7 = 0 1 1 1
15 = 1 1 1 1
DCEX?
code
The
FMTU
command instructs the generator to use the new setting. The
updates hardware to the new setting and redraws the test image.
DCBM 7
// Set mask to read sense lines 0, 1 and 2 only
DCEX 5
// Only lines 0 and 1 should be grounded
FMTU
// Update hardware to current buffer contents
ALLU
command
269
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