Xillybus for PXIe Chassis

Questions and discussions about the Xillybus IP core and drivers

Xillybus for PXIe Chassis

Postby Guest »

Really like xillybus. Can we adopt it when using some PXIe Chassis?

For example:
PXES-2301
6 All-Hybrid Slot 3U PXIe Chassis; AC Powered with Up to 8GB/s System Bandwidth
https://www.adlinktech.com/Products/PXI ... 01?lang=en


Best,
Guest
 

Re: Xillybus for PXIe Chassis

Postby support »

Hello,

Judging by section 4.2 in the PXIe specification [1] (see link below), all signals that are required by Xillybus (actually, the PCIe block Xillybus is attached to) are present to a PXIe peripheral slot, so Xillybus can be used in a board that is plugged into a PXIe box.

I would suggest contacting the FPGA vendor (Intel or Xilinx) for a guarantee that their native PCIe block supports PXIe. I would be quite surprised if it wouldn't.

Regards,
Eli

[1] http://www.pxisa.org/userfiles/files/Sp ... PEC_R1.PDF
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Re: Xillybus for PXIe Chassis

Postby Guest »

Hi Eli,

Thanks for your reply. It would be cool if one board can be used with xillybus. I am wondering if there are many FPGA boards are on the PXIe, would xillybus still work? And how should we program each card, in this case, using xillybus?

Best,
Chongxi
Guest
 

Re: Xillybus for PXIe Chassis

Postby support »

Hello,

Yes, Xillybus definitely supports multiple PCIe (or PXIe) cards on the bus. There are two possible ways to handle this:

(1) Configure different IP cores for each in the IP core factory, so that they appear with distinct device file names. The advantage is the simplicity of telling which card is which. If both cards do exactly the same thing, the downside is that different bitfiles need to be maintained just for the sake of this.

(2) Use a Xillybus driver which adds a numeric prefix to the device file names, which represents the card it belongs to (for example, xillybus_00_read_32 and xillybus_01_read_32 instead of xillybus_read_32). This driver is available for both Linux and Windows. Note that the numbers given by the driver aren't repeatable across booting the computer, so other means are required to tell which is which.

Regards,
Eli
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Re: Xillybus for PXIe Chassis

Postby Guest »

Great answer thanks Eli.

If I understand you correctly: everytime when the system reboots, we will have to write some value into and read it out to check which prefix number is assigned to which card then use that specific PCIe channel to collect data as using a single board. It is just in this case, we need to read from multiple streams (from different FPGAs) in the high-level program.

Best,
Chongxi
Guest
 

Re: Xillybus for PXIe Chassis

Postby support »

Hello,

I understand that you went for option (2).

It's actually simpler than that. The device files for all PCIe cards are all accessible by the host at all times. So it's sufficient to have a simple extra Xillybus stream that just outputs some identification code. I believe that the PXIe standard requires each slot to have a few pins that identify which slot the card is mounted in, so connect these pins to the FPGA, and expose that word through that dedicated stream.

Now you have a pairing between a physical position and the index assigned by Xillybus' driver, and from there the software can make its choices.

Regards,
Eli
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Re: Xillybus for PXIe Chassis

Postby Guest »

Awesome! Xillybus is great!

WIll try that soon. Will let you know how it goes.
Guest
 


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