Serial Data Interface with DAQ Card DIO-32HS or LABPC+

[kaktus]

Hi experts...

I want to write Serial data synchronised by a clock signal with the DAQ Card to an external device. What posibilities have I to implement this? Are there any example VI for this application?

The Data I have to write is a bitstream of 92 bits. The external device catches the serial data with the rising clock edge. I must generate the clock signal and the data signal.

regards Kaktus

[JB]

Dear Kaktus,

do you need to respect an accurate baudrate?
If not the problem can be solved very easily.
For example:
Data on Port A line 0 --> PA0
Clock on Port A line 1 --> PA1

What you need to do:
1) Wire your bitstream (array of boolean) to a FOR loop.
In the FOR loop:
1) Set PA1 to False
2) Write next data bit to PA0
3) Set PA1 to True (rising edge of clock)

If necessary (timing considerations of your hardware), insert delays in your loop.

I hope this helps.

[Nick-W]

kaktus,
You have one option with the Lab-PC+, as there is only one handshaking mode. You will need to send in your timing signal to the STB line for the port you are using (see user manual for deatils on line www.ni.com/manual). Transfer rate are less than 10k max. For examples open LV Examples: I/O Interfaces -> DAQ ->Digital -> Buffered Handshake I/O. Look at the 8255 section.
If you want to use the 32HS, you have 7 different methods of transfering data. The one that I think will be best for what you are doing is Pattern Generation. One set of data is input/output when a pulse comes in on the REQ line. You can go up to 5 MS/s with the PCI-6533 and 20MS/s with the PCI-6534. For timing diagrams, please see the 653x User Manual (www.ni.com/manuals.)
For LV Examples
, go to -> Digital -> Buffered Pattern I/O.
I would recomend using the 32HS, as the Lab-PC+ board is no longer in the NI Catalog.

Nick Wilson
Application Engineerin
National Instruments
www.ni.com/ask