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Topic: How does STEPPING effect JTAG programming (Read 2029 times) previous topic - next topic

How does STEPPING effect JTAG programming

Hi,

just a quick question I couldn't find much info yet.
I still try to program a xcf16p. However, the version of the board returns to be STEPPING 14.
urJTAG only contains STEPPING 0 in its stepping file
I added 14 so now the file looks like this

/usr/share/urjtag/xilinx/xcf16p/STEPPINGS
Code: [Select]
0000	xcf16p	0
1110    xcf16p  14

Just guess there is more work to do. Otherwise, all this stepping stuff in urJTAG would be kind of senseless.
Any idea where or how to make sure its working for other stepping versions.

Thanks

Re: How does STEPPING effect JTAG programming

Reply #1 –
Ok the question remains just out of curiosity. However, I extracted the bsdl files from the webpack installation.
and used

Code: [Select]
jtag> bsdl path ./bsdl
to point to those. Now ALL devices in the chain are detected correct.
I make little progress here ;)

Re: How does STEPPING effect JTAG programming

Reply #2 –
THe stepping has to do with urJTAGs processed/compiled bsdl library I think, so the BSDL frees you from those limite. I have had this issue on other chips, though the stepping changed enough that step 1 of XC9572XL is not programmable by urJTAG (v11) while stepping 0 is.
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Re: How does STEPPING effect JTAG programming

Reply #3 –
My question is more, how does the STEPPING influence programming in general including Xilinx own tools (impact).
Does stepping just refer to some minor silicon revision or does that include change in functionality which might be incompatible with older versions.

In urjtag the file STEPPINGS allow to assign a certain stepping of a part to a certain bsdl file.  Thus, I guess a change in functionality would require to assign a new/different bsdl file to this stepping version.

Xilinx itself provides several BSDL files for the same resp. similar parts
E.g. for the xcf16p you can find
xcf16p.bsd, xcf16p_1532.bsd, xcf16p_fs48.bsd, xcf16p_fs48_1532.bsd, xcf16p_vo48.bsd, xcf16p_vo48_1532.bsd

Urjtag ships with different versions too. However, providing the more specific versions from xilinx, urjtag switches over to that one. That's a bit odd in my opinion since bsdl files describe the chip and it should either fit or not. I can't see how one could say... it fits nearly if I do not have better options. However, maybe its using simply the most recent... not sure.

Re: How does STEPPING effect JTAG programming

Reply #4 –
Quote
Does stepping just refer to some minor silicon revision or does that include change in functionality which might be incompatible with older versions.

In my limited experience it is both. Sometimes minor and compatible, sometimes drastic.
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