sbRIO-9651 SoM FPGA fabric clock specifications.

[Michel_Gauvin]

Hello,

I'd like to know the following specifications regarding the FPGA clock (fabric clock) of the NI sbRIO-9651 SoM:

- Accuracy in (ppm)
- Aging (ppm/year)
- Temperature (ppm/°C)
- Skew (ppm)

I couldn't find anything related to this in the specification document.

Is it possible to use an external clock to repalce this one if the specifications doesn't meet our requirement? This clock would be provided through a custom carrier board.

Thanks,

Michel

[TheXiadow]

The 9651 uses Xilinx's Artix-7 FPGA, so I would suggest looking at Xilinx's documentation to find that information.

Artix-7 FPGA Family

http://www.xilinx.com/products/silicon-devices/fpga/artix-7.html#overview

They do have a very detailed document on clocking resources for the Artix-7s; if you're looking for more specific information, I might try contacting Xilinx.

7 Series FPGAs Clocking Resources

http://www.xilinx.com/support/documentation/user_guides/ug472_7Series_Clocking.pdf

Regarding using an external clock, the following forum post discusses this -- it should be possible to import an external clock into LabVIEW with the 9651.

Want to use external clock for SCTL on myRIO

http://forums.ni.com/t5/Academic-Hardware-Products-ELVIS/Want-to-use-external-clock-for-SCTL-on-myRI...

I hope this is helpful. Good luck!

[Michel_Gauvin]

Hello TheXiadow,

The specifications I'm looking for is the oscillator that NI puts on the SoM which provides the "Top Level" clock to the FPGA.

Thanks for the link, I will take a look at it.

Michel

[Deagle · Accepted solution]

Michel,

The accuracy of the clock is ±50 ppm. You can use an external clock as a source for single-cycle Timed Loops. The top-level logic -- things outside of SCTLs -- will still be controlled by the internal oscillator at 50 ppm but any logic or I/O that needs a different accuracy can be placed in a SCTL and use the external clock. There is some good information on how to import a clock on our Hardware Developers Community for NI Single-Board RIO and System on Module. Keep in mind that the amount of resources utilized and their toggle frequency will have an impact on the overall jitter of your system.

Thanks,

Bryan