usb jtag xilinx
Thanks for the leads. I have contacted the designer of USB2LPT. First, let me say that I have the utmost regard for his work. I think he has done a fine job. There are a couple of issues with his device. First, I am running XP and some XP machines have problems with his drivers. Secondly, he is building these devices by hand and therefore availability is low. Considering the costs involved in hand building small quantities, his price is very low. He is probably selling these at close to cost.
He would rather I would clone my own device(s) from his info on the web. (Should you wish to do that, please email the author as he wants to issue serial numbers for the EEPROM.)
The Xilinx solution is a possibility, but the prices I was quoted are huge. I may need to outfit a couple of laptops, so any price differential adds up quick. Also, I have several programmers for microcontrollers that only run from an LPT port. If I can get an LPT port working via USB, I can support these programmers from my laptop as well.
With regard to the MOSCHIP device, I do not seem to have gotten a good install on several XP boxes. My laptop will not run the device at all. Two XP desktops install the device, but its own internal loopback test fails. However, on a Win2K desktop, I did get it to install and pass the internal loopback test. Unfortunately, the WIN2K box does not have the IMPACT software installed, so I cannot test JTAG yet.
I will probably keep trying for the remainder of the week on the MOSCHIP device. If I cannot make any headway, I will probably buy a USB2LPT and hope I do not run into the WIN XP issue.
P.S. Yes, USB2LPT is slow. If you dig through his web-page, he mentions this fact and gives some numbers. However, I use JTAG only for programming. Since, loading new bits files does not happen that often for me even when prototyping, the speed issue is not a big deal.