DP83848YB: does not work in a JTAG chain

Alex Panos62

Part Number: DP83848YB
Other Parts Discussed in Thread: DP83848I-MAU-EK

I am having a problem daisy chaining two DP83848YB parts in a JTAG chain. I had problems on my board with my 6 device JTAG chain. I jumpered around the DP83848YB parts and everything runs fine.

Using the Corelis chain integrity debug tools and two of the DP83848I-MAU-EK eval cards. I can run chain integrity on each eval card independently and it passes just fine. When I daisy chain the two eval cards TDO to TDI they fail just like the chain on my PWA. Why do the DP83848YB parts not work in a JTAG chain?

over 5 years ago

0 Rob Rodrigues over 5 years ago

TI__Mastermind 19780 points

Hi Alex,

I am not aware of any JTAG issues with the DP83848 devices.

I have to look into a JTAG chain with 2 848 devices in my own lab setup. Please give me a few days to get back to you.

Best Regards,

0 Alex Panos62 over 5 years ago in reply to Rob Rodrigues

Prodigy 30 points

Great, thank you look forward to hearing back form you.

0 Rob Rodrigues over 5 years ago in reply to Alex Panos62

TI__Mastermind 19780 points

Hi Alex,

I was able to reproduce your error in my lab with 2 DP83848YB devices chained together. My JTAG controller reported the chain was broken 2 devices before TDO. Is this the same error you receive?

This doesn't appear to be an issue with the BSDL as far as I can tell. I don't have any internal history on an issue with JTAG chain for the 848 either.

Is it possible to implement a work around on your board for this issue?

Best Regards,

0 Alex Panos62 over 5 years ago in reply to Rob Rodrigues

Prodigy 30 points

Yes that is the same error I saw, and yes I agree the BSDL looks correct. We have already implemented a work around, thank you very much for following up and confirming my test results.

Thanks again,

Alex

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DP83848YB: does not work in a JTAG chain