How to select the PFI line to use on the AUX port of the 5761 ?

[Denn_Mann]

I understand that the CLIP I am using on my 5761 DAC allows me to access the 8 PFI lines.  However, when I access the peripherals of my 5761 in the project window by clicking the "+" sign next to the module name, I only see "PFI Input" and "PFI Output."  I have tried to get this to send a signal in the past but I was unable to determine how to select the PFI Line that I want to use.   How do I select the PFI line?

Any ideas?  I was able to get the PFI of my AWG (5422) to work and it is amazing.  I wish to control a digital step attenuator for a ground penetrating radar I am developing.

Your help and time is much appreciated. 

PS: I have been working with this PXI system (chassis,embedded controller, FPGA, digitizer 5761, and AWG) for 1 year and I am afraid it has come the time to learn this one way or another. 

Have a nice day!

-Daniel

[Denn_Mann]

I think I figured it out but havent tested it yet.  All you do is write a U8 number and depending on whether it is a 0 or 1 it will write a boolean LOW or HIGH depending on the location of that number.  Say I write U8 = 1 = 0000 0001, then (assuming the LSB corresponds to PFI 0), only PFI 0 will have a HIGH signal while the rest have a LOW.  This can be repeated for U8=16 = 0001 0000 in which case PFI 5 now has a digital HIGH while the rest are LOW.

  I will test it out in about two weeks when our PXI system return from Greeneland to Pennsylvania.  Yeahhh!

-Denn

[rschmeling]

Did this work for youwhen you tested it?  I am having the same issue and have tried this and I dont think that is is working properly.  Attached is the vi I created to test this.  The department electronics person built a test board for me to test the application before applying it to trigger my laser.  The LED is on the brad board and there is a buffer chip to give the voltage needed.  I run the attached vi to test to make sure that is cycles through turning on the LED.  Assuming that the test apparatus is all correct I am not able to trigger the LED to turn on using the AUX I/O port.  I programmed the value of 1 in to send a high signal to the AUX I/O0 line and nothing is happening with my LED.  Did I misunderstand how to use the aux i/o and the PFI line?

Thanks

Ryan

[ManuelQ]

Hi there,

I have the same problem using NI 5761 and the FPGA module 7952R in the PXI. I would like to generate an arbritrary binary sequence. But I couldn't figure out how to address a specific digital out channel channel.

However, for a start I simply wanted to test if I can set one of the digital outputs to high. Thanks to this post I tried what you can see in the pictures. The number is binary. See the screen shot to see my latest approach.

I could not measure any voltage. I will try it again tomorrow. Maybe I did something wrong with the format of the number I've put in.

Any hint would be appreciated! Thank you very much!

regards from Italy

[ManuelQ · Accepted solution]

I found the solution. In addistion to the node that is visible in my previous post, there must be a PFI write enable node with a decimal number input specifying the line to be enabled. Then, there must be a PFI Connector enabled node, set to true. Not sure if the latter node is really neccessary, though. Otherwise above examples should work as is. 

[patrick.m.mcc]

Hello. I am also having trouble. I am trying to output from the fpga to a switch on the outside. I have enabled the pfi connection. But I'm confused on the pfi write enable. What did you mean by decimal number at the input to the pfi write enable? Does the number correspond to the line number. So if I give the write enable a value of zero, it then enables pfi0. If I give it a value of 6 it enables pfi6? From what I see from the datasheet (attached) the pfi write enable tells the pfi port whether or not the line will be an input or output. Could you give me the values that worked for you so then I could test my system out with those values?

Many thanks,

Patrick

[patrick.m.mcc]

i figured it out. The write enable wasn't the problem. It was the output value I set it to. I was trying to output high on Aux0 and set it the write equal to '1'. However that corresponds to AUX7. For AUX0 the output needs to be '1000 0000'

Patrick