National Instruments NI USB-621x User Manual page 8

Contents
Chapter 7
Analog Output
Analog Output Circuitry................................................................................................ 7-1
AO Range ...................................................................................................................... 7-2
Minimizing Glitches on the Output Signal.................................................................... 7-2
Analog Output Data Generation Methods..................................................................... 7-2
Software-Timed Generations .......................................................................... 7-2
Hardware-Timed Generations......................................................................... 7-2
Analog Output Digital Triggering ................................................................................. 7-4
Connecting Analog Output Signals ............................................................................... 7-4
Analog Output Timing Signals...................................................................................... 7-5
AO Start Trigger Signal .................................................................................. 7-5
AO Pause Trigger Signal ................................................................................ 7-6
AO Sample Clock Signal ................................................................................ 7-7
AO Sample Clock Timebase Signal................................................................ 7-8
Getting Started with AO Applications in Software....................................................... 7-9
Chapter 8
Digital I/O
Static DIO...................................................................................................................... 8-2
I/O Protection ................................................................................................................ 8-2
Increasing Current Drive ............................................................................................... 8-2
Connecting Digital I/O Signals ..................................................................................... 8-3
Getting Started with DIO Applications in Software...................................................... 8-4
Chapter 9
Counters
Counter Input Applications ........................................................................................... 9-2
Counting Edges ............................................................................................... 9-2
NI USB-621x User Manual
Using a Digital Source...................................................................... 7-5
Routing AO Start Trigger Signal to an Output Terminal ................. 7-6
Using a Digital Source...................................................................... 7-6
Using an Internal Source .................................................................. 7-7
Using an External Source ................................................................. 7-7
Routing AO Sample Clock Signal to an Output Terminal ............... 7-7
Other Timing Requirements ............................................................. 7-7
Single Point (On-Demand) Edge Counting ...................................... 9-2
Buffered (Sample Clock) Edge Counting......................................... 9-3
Non-Cumulative Buffered Edge Counting ....................................... 9-4
Controlling the Direction of Counting.............................................. 9-4
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