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WB sel signal question
by lobachevskylai on Nov 18, 2011 |
lobachevskylai
Posts: 3 Joined: Nov 17, 2011 Last seen: Feb 6, 2015 |
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I am trying to design a wb2ahb bridge, and facing a question about wb_sel_o.
The WB bus width is 32-bit, so wb_sel_o is 4 bit, which is like a byte enable signal. Can the wb_sel_o signal be any possible case of the 4 bit (totally 16 cases)? or just only be byte select, word select or dword select, like 0001, 0100, 0011, 1100, 1111 or etc, and signal like 0101 , 1110 or etc are forbidden. I have read the WB3 Spec, where I have not found the notice about this. In my opinion, the case like 0111 is strange, and may not be used in real design. However, I need the 'official' notice. Is there anyone meet the 'strange' case about wb_sel_o? Do I need to consider the 'strange' case? |
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RE: WB sel signal question
by unneback on Nov 18, 2011 |
unneback
Posts: 20 Joined: Apr 24, 2004 Last seen: Oct 15, 2016 |
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The sel_o signals are byte enable signals and you do not need to bother with the strange cases
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RE: WB sel signal question
by lobachevskylai on Nov 18, 2011 |
lobachevskylai
Posts: 3 Joined: Nov 17, 2011 Last seen: Feb 6, 2015 |
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OK
Thx
The sel_o signals are byte enable signals and you do not need to bother with the strange cases
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RE: WB sel signal question
by rfajardo on Nov 18, 2011 |
rfajardo
Posts: 306 Joined: Jun 12, 2008 Last seen: Jan 6, 2020 |
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Hi,
if you want to be compatible with or1200, the cases handled by it are found in the file or1200_lsu.v lines 196-211. It is as Unneback said. |
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RE: WB sel signal question
by lobachevskylai on Nov 18, 2011 |
lobachevskylai
Posts: 3 Joined: Nov 17, 2011 Last seen: Feb 6, 2015 |
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Thx a lot!
I have read the code you said. It seems what I guess is correct. No more 'strange' case may be considered.
Hi,
if you want to be compatible with or1200, the cases handled by it are found in the file or1200_lsu.v lines 196-211. It is as Unneback said. |
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