© National Instruments Corporation 2-1 653X User Manual
2
Using Your 653XTo begin using your 653Xdevice, navigate this chapter in the following
order:
1. Choose the correct mode of operation to perform using the table below.
2. Follow the instructions for the application you want to perform.
3. Refer to pinout diagrams in Appendix C, Connecting Signals with
Accessories, when you are ready to connect your devices and/or
accessories.
Tip See the glossary for definitions to digital I/O terms used throughout this chapter.
Choosing the Correct Mode for Your Application
Use the following table to find the correct mode for your application:
Application Requirements Suggested Mode to Use
I need to perform basic digital I/O that does not need hardware timing or handshaking between
the 653X and the peripheral device.
Unstrobed I/O
I want to configure the direction of each bit individually instead of groups of eight. Unstrobed I/O
I want to connect two or more output drivers/pins to the same line. Unstrobed output with
wired-OR driver
I need to communicate with an external device using an exchange of signals to request and
acknowledge each data transfer.
Handshaking I/O–
Select appropriate
protocol
I want to start and/or stop acquiring data upon a trigger and/or to transfer data at timed intervals. Pattern I/O
I want the 653X to capture input data only when certain lines change states. Change Detection
I want to monitor activity on input lines without continuously polling or transferring
unnecessary data during periods of inactivity.
Change Detection