Forums

Trouble configuring Virtex-5 FPGA using JTAG

Started by Syed Huq October 13, 2014
I'm trying to configure a Virtex-5 FPGA on a custom board and I'm using Xil=
inx iMPACT in order to program the FPGA using a JTAG interface. But iMPACT =
has trouble detecting the FPGA and gives an error about not being able to d=
etect the FPGA even though it is powered on. I tried to program a similar b=
oard and I was able to do so without any issues. The board designed is a cu=
stom board so I'm wondering if there is something going wrong on the board =
itself or if it is a problem with the JTAG configuration. I use two differe=
nt cables for the different boards so I'm not really sure where the problem=
 lies.

I probed the JTAG signals on both the boards to see if the waveforms are co=
rrect and it looks like the waveforms are way off.

I've given links to the schematics of the two different boards and their re=
spective waveforms and it looks like there is something wrong with the cust=
om board.

Schematics : The schematics are only for the JTAG configuration

Evaluation Board : https://www.dropbox.com/s/j1l4pt7bd4qpzex/5%20FPGA%20Con=
fig.PDF?dl=3D0

Custom Board : https://www.dropbox.com/s/iqnic2giq4dcah6/JTAG.PDF?dl=3D0

Waveforms : The waveforms are when I use the Initiate Chain command from iM=
PACT

Evaluation Board : https://www.dropbox.com/s/zysyubc7hosfmg9/Eval_Init.jpg?=
dl=3D0

Custom Board : https://www.dropbox.com/s/hf93or6zr9wmi59/JTAG_Waveforms_B4_=
1K.jpg?dl=3D0

I'm not sure if there is something wrong with the JTAG cable itself or if t=
here is something else that is wrong with the fpga power etc.
On Sun, 12 Oct 2014 20:51:26 -0700 (PDT), Syed Huq
<syed.huq.a@gmail.com> wrote:

>I'm trying to configure a Virtex-5 FPGA on a custom board and I'm using Xilinx iMPACT in order to program the FPGA using a JTAG interface. But iMPACT has trouble detecting the FPGA and gives an error about not being able to detect the FPGA even though it is powered on. I tried to program a similar board and I was able to do so without any issues. The board designed is a custom board so I'm wondering if there is something going wrong on the board itself or if it is a problem with the JTAG configuration. I use two different cables for the different boards so I'm not really sure where the problem lies. > >I probed the JTAG signals on both the boards to see if the waveforms are correct and it looks like the waveforms are way off. > >I've given links to the schematics of the two different boards and their respective waveforms and it looks like there is something wrong with the custom board. > >Schematics : The schematics are only for the JTAG configuration > >Evaluation Board : https://www.dropbox.com/s/j1l4pt7bd4qpzex/5%20FPGA%20Config.PDF?dl=0 > >Custom Board : https://www.dropbox.com/s/iqnic2giq4dcah6/JTAG.PDF?dl=0 > >Waveforms : The waveforms are when I use the Initiate Chain command from iMPACT > >Evaluation Board : https://www.dropbox.com/s/zysyubc7hosfmg9/Eval_Init.jpg?dl=0 > >Custom Board : https://www.dropbox.com/s/hf93or6zr9wmi59/JTAG_Waveforms_B4_1K.jpg?dl=0 > >I'm not sure if there is something wrong with the JTAG cable itself or if there is something else that is wrong with the fpga power etc.
TCK shorted to TDO? -- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com