Deciding Which Lines You Want To Monitor; Deciding How To Start And Stop Data Transfer-Triggering - National Instruments 653X User Manual

Deciding Which Lines You Want to Monitor

Deciding How to Start and Stop Data Transfer—Triggering
© National Instruments Corporation
Table 2-4. Port and Timing Controller Combinations (Continued)
Transfer Possible Port
Width Combinations
16 bits Port 0, Port 1
Port 2, Port 3
32 bits Port 0, Port 1, Port 2, Port 3
You need to specify which of the lines in your acquisition you want to
monitor for changes.
Specify which bits are significant to you by using a software line mask in
the
DIG_Trigger_Config
Digital Trigger Config VI for LabVIEW. In the following example, the user
specifies the mask to detect changes on the two least-significant bits of a
port. Pattern 1 does not have changes in the two bits of interest and data is
not latched, but for pattern 2, a change is detected on one of the two bits of
interest, and the value of the entire port is acquired.
Mask
Initial Input
Pattern
Input Pattern 1
Input Pattern 2
Figure 2-15. Change Detection Example Settings
By default, data transfer starts upon a software command (the
Digital Buffer Control VI called by the DIO Start VI in LabVIEW and the
and
DIG_Block_In DIG_Block_Out
However, you have the option of using a hardware trigger to start, stop, or
start and stop data transfer.
function in NI-DAQ C interface, and the
0 0 0 0 0 0 1 1
0 0 0 0 0 0 1 0
0 1 0 0 0 0 1 0
0 0 0 0 0 0 1 1
functions in NI-DAQ C interface).
2-27
Chapter 2 Using Your 653X
Timing Controllers
That Can Be Used
Group 1
Group 2
Group 1
No change on specified
bits.
Data is not latched.
Change detected,
latch entire port.
653X User Manual