National Instruments DAQ S Chapter 8 Programmable Function Interfaces (PFI), Chapter 9 Digital Routing and Clock Generation

Contents
© National Instruments Corporation ix NI 6124/6154 User Manual
Frequency Output Signal.................................................................................7-30
Routing Frequency Output to a Terminal.........................................7-30
Default Counter/Timer Pinouts......................................................................................7-30
Counter Triggering........................................................................................................7-31
Other Counter Features..................................................................................................7-32
Cascading Counters.........................................................................................7-32
Counter Filters.................................................................................................7-32
Prescaling........................................................................................................7-33
Duplicate Count Prevention............................................................................7-34
Example Application That Works Correctly (NoDuplicate Counting) ... 7-35
Example Application That Works Incorrectly (Duplicate Counting).... 7-36
Example Application That Prevents Duplicate Count......................7-36
When To Use Duplicate Count Prevention.......................................7-37
Enabling Duplicate Count Prevention in NI-DAQmx......................7-37
Synchronization Modes...................................................................................7-37
80MHz Source Mode .......................................................................7-38
Other Internal Source Mode..............................................................7-39
External Source Mode.......................................................................7-39
Chapter 8
Programmable Function Interfaces (PFI)
PFI for Non-Isolated Devices........................................................................................8-1
PFI for Isolated Devices................................................................................................8-2
Using PFI Terminals as Timing Input Signals...............................................................8-4
Exporting Timing Output Signals Using PFI Terminals............................................... 8-4
Using PFI Terminals as Static Digital Inputs and Outputs............................................8-5
Connecting PFI Input Signals........................................................................................8-6
PFI Filters......................................................................................................................8-6
I/O Protection.................................................................................................................8-8
Programmable Power-Up States....................................................................................8-8
Chapter 9
Digital Routing and Clock Generation
Clock Routing................................................................................................................9-1
80MHz Timebase ...........................................................................................9-2
20MHz Timebase ...........................................................................................9-2
100kHz Timebase ...........................................................................................9-2
External Reference Clock................................................................................9-2
10MHz Reference Clock ................................................................................9-3
Synchronizing Multiple Devices ...................................................................................9-3