Trouble using ChipsCope Pro with MicroBlaze

Hi all,

Has anybody tried Chipscope Pro with a MicroBlaze based system?

I am using JTAG-Uart for debugging purposes and now I want to use ChipScope Pro at the same time, but when I try to implement it generates an error with BSCAN.

I know that JTAG-Uart uses a BSCAN and ChipScope also needs another one. If I take out the JTAG-Uart from the design it works.

So is there any possible solution to this?

I am using a 1000 million gate Virtex II FPGA.

Any help would be welcome.

Thanks in advance,


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There is single BSCAN per FPGA, that BSCAN instance has two "user" instructions.

If either JTAG UART or ChipScope uses both user instructions then it most likely is nogo with JTAG Uart and ChipScope at the same time, if both use only one user instruction then it could at least theoretically be possible. But I think it is not possible at this time.

Ok, I can confirm at current time it is not possible: if you look at opb_jtag_uart RTL sources you see that even it is using only one user instruction from the 2 available ones it uses the BSCAN instance in a way that it can not be shared with Chipscope,

and second - even it would worked, I think XMD and ChipScope can not share the JTAG interface so it wouldnt work anyway


Reply to
Antti Lukats

I'm successfully using Chipscope Pro with a Microblaze system, but I'm using UART Lite instead of JTAG UART. Change the UART and enjoy the nice waveforms that Chipscope produces (it took me some time to learn how to use Chipscope though, but it was worth it in the end).

Cheers Johan

Reply to
Johan BernspÄng

Yes we have done this many times.

Only one application can take ownership of the JTAG cable and attached BSCAN component, so to be clear, you can create a single netlist that will work with both applications, but you can not have both applications using the cable simultaneously.

You need to generate the Chipscope ICON core without a BSCAN component. This is a checkbox in the GUI. There will be a number of new signals on the ICON component that then need to be attached to the BSCAN component that has already been instantiated in the opb_jtag_uart. The jtag_uart uses scan chain 2, so scan chain 1 is available for chipscope.

I would highly recommend adding a BUFG to the BSCAN DRCK2 signal in the OPB_JTAG_UART when making the modifications, as we saw rather flaky behavior from the core (without floorplanning to account for local clocking). A BUFG was the easiest solution for us, as we had plenty of them left.

Unfortunately, we can not distribute the code for our modified OPB_JTAG_UART without permission of Xilinx, as it is based on their copyrighted code. Fortunately there is now source code in EDK 6.1i, so the instructions herein should be sufficient. The MicroBlaze team does have our code, but has not chosen to include it in the distribution.

Regards, Erik Widding.

Birger Engineering, Inc. -------------------------------- 617.695.9233
100 Boylston St #1070; Boston, MA 02116 --------
Reply to
Erik Widding

Thanks a lot for your help!!!

Best regards,


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It's me again.

Looking at Erik's details I have continued the the next steps:

- Create a XPS proyect with JTAG Uart included in it.

- Export to Project Navigator.

- Include an ICON Core Disabling the BSCAN instantiation so that it shows the pins in the instantiation file.

- Take the JTAG Uarts source core and modify so that BSCAN component can be instantiation from the top level.

- Modify the top level so that the ICON uses the user port 1 of BSCAN. (There some signals that need to be shared. I have used an OR gate in those signals).

Once I have implement the final design it doesn't work neither of both, I mean ChipScope and XMD.

Someone any Idea what am I doing wrong?

Thanks in advance,


PD. Thanks Erik for the help.

Reply to


What version of EDK and ChipScope are you using?

Göran Bilski

arkaitz wrote:

Reply to
Goran Bilski

EDK 6.1 SP1 ChipScope Pro 6.1



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