JTAG-HS2 Programming Cable Issue

[Shani Kleinman]

Hi,

We are using Metaware debugger with Digilent JTAG-HS2 cable Rev.A for JTAG connection.  When 20 taps are in the chain, the chain is identified and we are able to connect to every processor and do single wr/rd, but failed to download data with some of the processors. In waves, we noticed that between successful write transactions we see an unexpected command of 4 clocks of high TMS with low TDI that coming from the driver.

When reducing number of participating taps in the chain to 16, we are able to download to all remained processors successfully. 

The issue is consistent with other HS2-RevA cables. 

Issue sound similar to the following post in the forum: 

Is there any known HW issue in the cable or in the driver?

Thanks.

 

Edited March 7, 2021 by Shani Kleinman

[JColvin]

Hi @Shani Kleinman,

I talked with the other engineer who responded to that other thread that you linked and they let me know that based on what you described with the clocking, then Metaware is calling one of the DJTG API functions and encountering this issue. However, they/Digilent doesn't really have a way of debugging calls that are being made/handled by the software, so you will need to contact Synopsys/Metaware to discuss this further.

Thanks,
JColvin

[AmitTewarii]

Hi JColvin , 

                     We are facing the same issue as mentioned in the query below. We are using Metaware Debugger connected with Digilent Cable. Can you help us understand the root cause of the issue and any earlier relevant fix for it . 

 

JTAG hangs if we have ODD number of processors in JTAG chain . 

If we add another JTAG Tap towards start of chain , JTAG still keeps hanging . 

But if we add another JTAG TAP towards end of daisy chain , the JTAG starts responding and can or RD/WR. 

 

 

Thanks, 

Amit 

[JColvin]

Hi @AmitTewarii,

I responded to your other thread here:

Thanks,
JColvin