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Visitor
Visitor
1,225 Views
Registered: ‎06-22-2017

GTX clock Contraint for multiple instances

Hiya,

 

I'm using Vivado 15.4 and have a core which contains a GTX. I have created multiple instances of this core but get the following warning:

[Constraints 18-619] A clock with name 'design_1_i/ATR_sFPDP_Lite_AXI_0/U0/ATR_sFPDP_Lite_AXI_v1_0_S00_AXI_inst/sfp_impl/gtx/inst/sfpdp_gtx_1_i/gt0_sfpdp_gtx_1_i/gtxe2_i/TXOUTCLK' already exists, overwriting the previous clock with the same name. ["c:/Scratch/project_2/project_2.srcs/sources_1/bd/design_1/ip/design_1_ATR_sFPDP_Lite_AXI_0_0/src/sfpdp_gtx_1/sfpdp_gtx_1.xdc":72]

 

This warning seems to be because the .xdc generated by the GTX wizard has the following lines:

create_clock -period 16.0 [get_pins -hier -filter {name=~*gt0_sfpdp_gtx_1_i*gtxe2_i*TXOUTCLK}]
create_clock -period 4.0 [get_pins -hier -filter {name=~*gt0_sfpdp_gtx_1_i*gtxe2_i*TXOUTCLKFABRIC}]
create_clock -period 4.0 [get_pins -hier -filter {name=~*gt0_sfpdp_gtx_1_i*gtxe2_i*RXOUTCLKFABRIC}]

 

As the clock names don't include the block instance name then Vivado thinks that it is getting the same clock multiple times.

 

I have tried running:

set_property SCOPED_TO_REF <instance name>  [get_files <xdc name>]

 

But I still get the same warning.

 

Any ideas?

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Moderator
Moderator
1,218 Views
Registered: ‎09-15-2016

Hi @uhohrobbo

 

Have look at the solution given in the below AR:

https://www.xilinx.com/support/answers/59799.html

 

Hope this helps.

 

Regards

Rohit

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Regards
Rohit
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Visitor
Visitor
1,211 Views
Registered: ‎06-22-2017

Thanks @thakurr

So the solution to my issue is to modify the automatically generated .xdc file. I'm running in project mode, so will have to keep on modifying the .xdc file whenever the gtx core gets rebuilt? Isn't there a more elegant / permanent solution?
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Visitor
Visitor
1,206 Views
Registered: ‎06-22-2017

@thakurr I've actually just noticed that the -name attribute isn't applied, so I don't thin AR59799 will fix my problem.
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Moderator
Moderator
1,191 Views
Registered: ‎09-15-2016

Hi @uhohrobbo

 

Can you do report_clocks on the synthesized or implemented design and see if there are actually same clock with name TXOUTCLK created?

 

Regards

Rohit

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Regards
Rohit
----------------------------------------------------------------------------------------------
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