8452 SPI - Tristate output line

[TonyArris]

With the 8452, Is it possible to tri-state the output line for the read portion of a SPI read command? I am trying to connect to a bi-directional SDIO line on a device but if the 8452 is driving out during the read byte portion of the transaction, it wont work.

[NabilahF]

Hi Toni,

I am an Applications Engineer at National Instruments.Two different methods that you can use are: 

#1: Include NI-845x SPI Script Disable SPI.vi in your SPI script. This tristates the pins on the SPI port specified by the NI-845x SPI Run Script.vi, including all chip select pins. 

#2: Programmatically reset the NI-8452 by undetecting & redetecting it at the USB port level. One method to do this is through the DevCon command line utility from Microsoft. 

For the first option, page 9-43 of the NI-845x Hardware and Software Manual [1] documents the functionality of this VI.

For the second option, the DevCon utility acts as an alternative to Device manager. It can enable, disable, restart, update, remove, and query individual devices or groups of devices.

The necessary steps for this option are: 

1. Extract and place devcon.exe in your C:\Windows\System32 folder 
2. Open LabVIEW as an Administrator, then open Command Line Operations from LabVIEW 
3. Run Command Line Operations.vi 

Additional information on the DevCon utility and the remove operation can be found online [3] [4]. 

[1] http://www.ni.com/pdf/manuals/371746c.pdf 
[2] http://techlikes.com/2010/09/25/devcon-problem-in-windows-7-solved.html 
[3] http://msdn.microsoft.com/en-us/library/windows/hardware/ff544746(v=vs.85).aspx 
[4] http://msdn.microsoft.com/en-us/library/windows/hardware/ff544796(v=vs.85).aspx 

I hope this helps. Thanks and have a great day! 


Regards,