Today I had a talk with the representant of Xilinx in russia. He adviced me to use Parallel cable 4 and not USB cable butwhen I asked why he told me that US Xilinx guys told him so. Can some one explain me? I need concrete examples. Perhaps he is only interested to sell ... one day he'll sell parallel cable ... and than I'll discover that I need the USB and come back to him to buy it :))
The USB cable is a recent product and may not be a 100% happy experience. I purchased one a couple weeks ago and found a few things.
1) I think it properly works at USB2.0 hi-speed but Windows XP reports the device is a high-speed device plugged into a full-speed port and that the device can go faster. I spent too much time trying to get the speed out of the device when it is probably already up to speed.2) Because it's new, Synplicity's Identify tool doesn't have the driver for this "proprietary interface." Maybe in the next software rev (or two) but not now.
From what I've seen physically, I think the interface to the electronics are the same for the two cables. Both have the ability to work with low I/O voltages at the device side so, for instance, a 1.8V JTAG chain could be accessed with either cable. Both are powered from the PC, the USB cable via the USB power and the Parallel-IV cable through a keyboard power jumper. My board-powered Paralell-III didn't work so well with a 2.5V powered JTAG chain.
If you have reliable USB2, can ignore the Windows warning messages, don't need to work with non-Xilinx tools, and the cable is available, go for the USB.
- John_H
"John_H" schrieb im Newsbeitrag news:KU95f.21$ snipped-for-privacy@news-west.eli.net...
Xilinx USB Cable is high speed device so WinXP gives warning if you plugit into FS host port or hub. this normal. A HS device can not operate at HS in FS port.
Cable IV vs USB Cable, the pld inside is either XCR3384 (Cable IV) or XC2C128 (usb cable). usb cable uses cypress hs usb chip. note that sub cable can update its PLD (cable IV can not in the factory shipped sate), also usb cable loads its firmware after enumeration, it does not contain firmware eeprom, only VID/PID eeprom. that makes usb cable upgragedable. And that is also one of the reasons why it is very likely that 3rd party products will never support xilinx usb cable. :(, as soon as any 3rd party implements usb cable support then it is only good as long as next impact service pack updates the usb cable
usb cable is annoying as it usually requires to replug the usb cable each time you replug the jtag cable or power off the fpga. this is really annoying sometimes.
so my favorite is still cable IV, IF it works, unfortunatly my home workstation has no LPT port and on the new workstation there is standard ECP port but xilinx cable IV drivers dont work in high speed mode.
so:
1 cable IV, use it if you can 2 usb cable, use if you cant use cable IVas xilinx is pushing usb cable, it is very likely that xilinx never fixes the issues with the cable IV driver installation.
Antti
I can't plug my american hair dryer into the european socket? I can make it fit! ...
The point I was trying to make is that I take my HS device (Platform Cable - USB), plug it into a HS port (Dell Optiplex GX280 USB2.0 Root Hub), and WinXP (Service Pack 2) complains that a HS device is plugged into a non-HS port and gives suggestions on HS ports to plug into... the ports I'm trying to use.
Something appears to be messed up in the implementation such that Win XP gets confused as to what is HS and what isn't. It appears that - despite the warning - I am running at HS.
"John_H" schrieb im Newsbeitrag news:opb5f.23$ snipped-for-privacy@news-west.eli.net...
hm ok, in that case yes it strange, it could be that the xilinx usb cable FW is not fully compliant to the usb spec and that triggers the warning, even though the cable operates at HS. I get this same warning myself but I havent bothered to check if the port is HS or not, I guessed its FS, and assumed that is the reason why I see the same warning. hum no, that cant be it, if the device is recogniyed as HS and FS root hub warning is geiven then this more likely an issue of mr Bill.
Antti
Ok thanks a lot for answers. Remains one question abour usb cable. I plan to use Xilinx BaseX and Xilinx EDK in Linux. Can some one make a Parallel IV vs. USB cable in Linux ?
Look for the comp.arch.fpga newsgroup thread entitled "Linux and Platform USB Cable" that was started on October 13th, 2005.
The "Dynamic FPGA Probe" software on our Agilent Logic Analyzer does support the USB-cable. At least it says that it detects a "Platform USB Cable" and specifically lists both parallel and USB cables for connections to FPGAs But the device only has a USB1.1-port on which I've never been able to get the thing running (not even with iMPACT or Chipscope on other machines).
I've had no problems with that so far. But I do have to close the cable connection and reconnect each time I power down the FPGA. Otherwise it works fine (at least when you use Chipscope to program, haven't tried with iMPACT).
cu, Sean
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