Quantum Data 881, User Manual

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882 Video Test Instrument User Guide (Rev A.35) 269
DCEX
Display Code EXpected
Class Format parameter settings
Description 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.
Command syntax 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
Query syntax DCEX?
Query response code
Other required
commands
The FMTU command instructs the generator to use the new setting. The ALLU command
updates hardware to the new setting and redraws the test image.
Example
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