Contents
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National Instruments Corporation
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DAQ-STC Technical Reference Manual
Programming for a GPCT Operation .................................................4-17
4.6.1.1
Overview.......................................................................4-17
Notation ........................................................................4-18
Resetting .......................................................................4-18
Arming ..........................................................................4-18
Simple Event Counting .................................................4-19
Buffered Event Counting ..............................................4-20
Relative Position Sensing .............................................4-23
Single-Period and Pulsewidth Measurement ................4-24
Buffered Period, Semiperiod, and Pulsewidth
Measurement..............................................................4-26
Pulse and Continuous Pulse-Train Generation .............4-28
Frequency Shift Keying ................................................4-31
Pulse-Train Generation for ETS ...................................4-33
Reading the Counter Contents ......................................4-34
Reading the Hardware Save Registers..........................4-34
Counter/Timer Output Pin .........................................4-35
Bitfield Descriptions...........................................................................4-35
Timing Diagrams................................................................................................4-53
4.7.1
CTRSRC Minimum Period and Minimum Pulsewidth......................4-55
CTRSRC to CTROUT Delay .............................................................4-55
G_GATE Minimum Pulsewidth.........................................................4-56
CTRGATE to CTROUT Delay ..........................................................4-57
CTRGATE to INTERRUPT...............................................................4-57
CTRGATE Setup................................................................................4-58
CTR_U/D Setup .................................................................................4-59
Detailed Description...........................................................................................4-61
4.8.1
Internal Signals and Operation ...........................................................4-62
G_SOURCE Selection and Conditioning...........................................4-63
G_GATE Selection and Conditioning................................................4-64
G_UP_DOWN Control ......................................................................4-64
G_OUT Conditioning and Routing ....................................................4-65
G_CONTROL Conditioning ..............................................................4-67
Gate Actions .......................................................................................4-67
4.8.7.1
START/STOP on G_CONTROL .................................4-68
Save on G_GATE .........................................................4-68
Reload on G_CONTROL .............................................4-68
UP/DOWN on G_CONTROL ......................................4-69
Generate Interrupt on G_GATE....................................4-69
Change Output Polarity on G_GATE ...........................4-69
Select Load Register on G_CONTROL .......................4-69