Re: unknown devices in JTAG chain

Mark,

Thanks a lot for your help. I had the same problem: the leads to the board
were to long (I made a PC3 on my own). So I shortened it (to about 10cm),
took a parallel port extension cable and it works fine. Thank you and the
other supporters once more...

Kay


"Mark van de Belt" <[EMAIL PROTECTED]> schrieb im Newsbeitrag
news:[EMAIL PROTECTED]
> Hello,
>
> I had the same problem with the same two chips. There were 13 devices on
the
> my board. I used long leads (20 cm) from the PC3 to the board. After
> shortening both the parallel port cable (I used a 1.5 M 1:1 extension
cable
> between the parallel port and the PC3 cable) and the leads to the board
(to
> 5 cm) the problem was solved.
>
> Mark
>
>
> "Kay Schubert" <[EMAIL PROTECTED]> schreef in bericht
> news:[EMAIL PROTECTED]
> > Hi,
> >
> > I designed a FPGA prototyping board with a Spartan XC2S200E and a
XC18V02
> > PROM.
> > To configure these devices I put a JTAG header on the board and routed
it
> as
> > described in
> > the following Xilinx datasheet:
> > http://toolbox.xilinx.com/docsan/xilinx4/data/docs/pac/designing7.html
> >
> > At the software-side I use impact and the PC3 from Xilinx. When I start
> > impact in boundary-scan mode,
> > the PC3 will be detected (as [EMAIL PROTECTED]) and  the boundary-scan chain
will
> > be identified. But there's the problem:
> > impact always detects 11 devices in the chain, but there are only two.
> > And: Even though the two devices are original Xilinx parts, no ID codes
> were
> > returned (or better: the returned codes
> > don't match with Xilinx parts).
> >
> > I checked the configuration connections and the power supply, but
> > everything seems to be o.k. Has anybody of you an idea what the problem
> > could be?
> >
> > thanks, Kay
> >
> >
>
>
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