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softwind555
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Registered: ‎05-14-2015

the usage of attributes

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Hello, in one of VHDL file generated by Xilinx, a lot of attributes,as listed in the code below, are used. I'm trying to find a document which have a complete explanation about the usage of all those attributes in VHDL. Does anybody know about it?

 

attribute shreg_extract : string;
attribute shreg_extract of cross_clk_bit : entity is "no";

attribute DowngradeIPIdentifiedWarnings: string;
attribute DowngradeIPIdentifiedWarnings of rtl : architecture is "yes";

attribute ASYNC_REG : string;
attribute SHIFT_EXTRACT : string;
--  attribute RLOC          : string;
attribute ASYNC_REG of data_sync : signal is "TRUE";
attribute SHIFT_EXTRACT of data_sync : signal is "NO";
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evgenis1
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Registered: ‎12-03-2007

Hi @softwind555 , 

 

You can find synthesis attributes in Vivado Synthesis Guide,  Xilinx U901 , VHDL chapter 4.

 

Thanks,

Evgeni

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evgenis1
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Registered: ‎12-03-2007

Hi @softwind555 , 

 

You can find synthesis attributes in Vivado Synthesis Guide,  Xilinx U901 , VHDL chapter 4.

 

Thanks,

Evgeni

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softwind555
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Registered: ‎05-14-2015
Thank you. Eveni.
I found a lot of definitions of attributes in this document.
But, still can't find "SHIFT_EXTRACT" and "DowngradeIPIdentifiedWarnings". Do you konw where i can find them?
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evgenis1
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Registered: ‎12-03-2007

Hi @softwind555 , 

 

Many attributes are generated by the tools, but not intended to be used by developers. If they're not in the synthesis guide than that's the case. Synth guild is supposed by the the "ultimate" guide for attributes, as far as I know.

Sometimes you can find better description for synthesis and implementation tool options in TCL shell help. But not for the attributes.

 

Thanks,

Evgeni

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