Xilinx xc 9572 (not xl)

Hi Everyone,
I have seen some posts here previously with schematics on how to build a card to attach to the parallel port using 2 IC's a couple of diodes and some resistors for programming the Xilinx XC9572 in circuit.

My question comes down to this. All the posts I have seen all showed a card that attached to the parralel port, would it make any difference or would there be any difficulty in the respect of the card being in the middle of two bits of sheilded cable?

Cheers in advance, Im new to these CPLDs but have a couple of thousand brand new ones.

I haven's seen the actual circuit you are referring to but i have made a Xilinx cable III with a plug directly to the parallel port and then use a cable 1 meter long (UTP) from the jtag pins to the chip and i had most of the times error writing the code to the chip.
I found that it is much better to use a long cable from the parallel port and then use the programmer circuit near the chip with a short cable, this works fine now.
I don't know in what distance you want to place the programmer but i would suggest to use the long part of the cable to the parallel port side since it is designed to drive long (not very long) printer cables.

Alex

Hi,
Thanks for the response, that confirms one of my initial thoughts whivh was that the programmer may get picky depending on how its connected.
The circuit that I saw was made to connect directly to the parallel port but my plan is to **** up a parallel cable I have which is about 4m long so it would be DB25 at the parallel connector then a length of cable to an IDC connector on the programming card and another IDC to which the cable would be connected which hooks into the JTAG header.
I was asking this question because I didn't know what to do about frame ground, obviously on the card attaching to the parallel port directly - no problem as one is right next to the other but where would it hook to on a wired cable? is there a pin which you have specificly hooked up on the card end that youve used for this purpose or its it a case of hooking up the sheild in the cable at both ends to FG?

Cheers in advance.

I have a self made xilinx cable IIII without any box.
If i judge from shielded audio cables then it is best to connect the shield of the parallel port only to the pc end (so that all the noise goes there and there is no gnd loop) and only connect the gnd of the internal cables to the pcb.
If you have a ready made parallel port cable then it is already connected to both sides so you can oly seperate the gnd at the plug of the pcb whick may be difficult.
You can try the way that is easyer first and if you have program errors then you can change it.
4 meters is kind on the long side for the cable but (i think 4-5 is the max you can use) if it works for a printer it should work for the programmer too.

Alex