National Instruments 653X - Manual (Page 24)

Chapter 2 Using Your 653X
653X User Manual 2-6 ni.com
• LabVIEW—Use one of the top-level VIs: the Read From Digital Line
VI to read from a digital port, and the Write to Digital Line VI to write
to a digital port. The digital channel number is 4 and the port width is
4. If one of the control/timing lines is used or reserved and you are
using the write or read port VIs, use the Line Mask parameter in the
DIO Port Write VI to mask out the appropriate lines.
Transferring Data Between Two
Devices—Handshaking I/O
If you want to communicate with an external device using an exchange of
signals to request and acknowledge each data transfer, use the handshaking
I/O mode.
Deciding the Width of Data to Transfer
You can choose between a width of eight, 16, or 32 bits. Use the following
table to find the valid combinations of ports and timing controllers you can
use based on the width of data you want to transfer.
Deciding Data Transfer Direction
You can choose to send data from the 653X device to the peripheral device
(output) or from the peripheral device to the 653X device (input).
Table 2-2. Port and Timing Controller Combinations
Transfer
Width
Possible Port
Combinations
Timing Controllers
That Can Be Used
8 bits Port 0 (DIOA<0..7>) Group 1
Port 2 (DIOC<0..7>) Group 2
16 bits Port 0, Port 1 Group 1
Port 2, Port 3 Group 2
32 bits Port 0, Port 1, Port 2, Port 3 Group 1