Measurement Computing ADAC-LVi User Manual

Page 69

Chapter 2 Digital I/O VIs

ADAC LabVIEW VI

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Special IO Control The SpecialIoControl controls the BIT CATCHER
operation mode. Port DIN0 may be configured to return the state of the
bit catcher, instead of the actual port data by setting the associated bit
to "1" in the Special Io Control. If a bit is so programmed, the port will
return "0" for that bit until a "1" occurs at the input. The port will then
read back a "1" even if the "1" goes away. When the DIN0 port is
serviced by the driver, each bit enabled and in the "1" state will read
automatically reset and ready for the next input transition. For detailed
definitions see the 5600 manuals ADVANCED PROGRAMMING
TECHNIQUES. When the Port Resolution is set for 16 bit mode,
Special Io Control is set in WORDs b(1111111111111111).

Pattern Polarity The PatternPolarity, PatternTransition and
PatternMask define the match condition for the Port Mode
Specification AND / OR modes.

For example on can define a match condition as bit 1, bit 2 and bit 3 all
set = "1" as a valid match (AND mode) by setting the following.

Port Mode Specification = AND
PatternPolarity = (b) 1110
PatternTransition = (b) 0
PatternMask = (b) 1110

Alternately, one can define a match condition as any one or more of bit
1, bit 2 and bit 3 having set = "1" by changing the Port Mode
Specification to OR mode.

PM(n) PT(n) PP(n) Pattern Match Bit Definitions
0 0 0 or 1 Bit Masked Off
0 1 0 or 1 Any Transition
1 0 0 ZERO
1 0 1 ONE
1 1 0 ONE to ZERO Transition
1 1 1 ZERO to ONE Transition

For detailed definitions see the 5600 manuals ADVANCED
PROGRAMMING TECHNIQUES. When the PortResolution=16,
PatternPolarity, PatternTransition and PatternMask are set in WORDs
b(1111111111111111).