Modprobe not working?

Questions and discussions about the Xillybus IP core and drivers

Modprobe not working?

Postby DeltaLux »

I would like xillybus to work without having to restart the computer. I just figured out how to make the FPGA program itself at boot-up, but the computer boots too fast. I use the command "sudo modprobe xillybus_pcie", but no device files appear under /dev. Any ideas?

Thank you
DeltaLux
 
Posts: 4
Joined:

Re: Modprobe not working?

Postby support »

Hello,

What's your setting? How do you program the FPGA? From the flash? From another computer? From the same one that the FPGA card sits on (which isn't necessarily a good way, but anyhow)?

Is it a dedicated system (like a box doing some specific task) or just any computer?

Regards,
Eli
support
 
Posts: 802
Joined:

Re: Modprobe not working?

Postby DeltaLux »

It is a Linux 16.04 computer. The AC701 board sits in the only PCIe slot of this computer. The FPGA programs itself through the SPI flash, but I have the same problem when I program the FPGA using an external computer through the micro-USB port. Through the design process I have always simply restarted the computer and it works fine. But now that we are finishing things up would like it all to work automatically. The only workaround I can think of is use a pin on the FPGA to turn on the motherboard when it is done programming. Not exactly sure what you mean about the last question. But pretty much the computer and FPGA and being designed to always be used for the purpose of a custom soundcard.
DeltaLux
 
Posts: 4
Joined:

Re: Modprobe not working?

Postby support »

Hello,

In principle, I can think of three directions:

(1) Speed up the configuration of the FPGA from the SPI flash by setting the configuration clock's frequency, if you haven't done that already. I'm however not sure if that will be fast enough.
(2) Apply the TANDEM technique to partially configure the FPGA quickly at powerup so it presents an PCIe interface, and then do the complete configuration at a longer time.
(3) Hold the PC's reset button wire asserted with a pullup/pulldown resistor, and deassert this reset signal one of the FPGA's pins once it's configured (probably through a FET transistor, depending on the voltage on the reset wire). Since the FPGA's pins are all high-Z until it's configured, all you need to do is to assign a constant value to this line in the logic design.

I believe option (3) will be simplest to pull off. The only annoying thing is that if you configure the FPGA through the JTAG cable while the PC is up, you'll have an abrupt reset. It's a refined version of your suggestion to power up the motherboard.

Regards,
Eli
support
 
Posts: 802
Joined:


Return to Xillybus