68 pin DDC connector for 6551

[ajog]

The 68 pin DDC connector for the PXI-6551 is missing a pin for PFI0. 

However, PFI0 is accessible via the flying lead cable.  

How can we access PFI0 using the 68 pin DDC connector?  Has this been assigned to one of the reserved pins?  Please advise.

Anand

[Keith.Shapiro]

Hi Anand,

Use of PFI0 on the flying lead cable is only available for the PCIe/PXIe 6535, -36, and -37. There is no way to access PFI0 via the DDC connector on a 6551.

Thanks,

Keith Shapiro
National Instruments R&D

[ajog]

Thanks Keith.  The PFI0 terminal is located on the front panel.

Also, it outputs NRZ binary data.  Does this mean it can be used to supply a DC voltage by outputtng all '1's?

Will it also be subject to the condition that all generation channels will have the same high and low level voltages?

Please advise.

Anand

[Keith.Shapiro]

Hi Anand,

You can use PFI0 to output a DC voltage by outputting all '1's, yes. There are some other ways to get a constant '1' level from a PFI line, too, that might be easier to deal with than trying to set up a data pattern to the PFI line.  Keep in mind that the output voltage is subject to drive strength limitations like all of the rest of the 6551's outputs.

Also, you are correct - PFI0 will be the same output voltage levels as the rest of the generation channels.

Keith Shapiro

National Instruments R&D