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Adventurer
Adventurer
6,306 Views
Registered: ‎06-20-2013

How do I know if DIFF_TERM is set to be TRUE correctly in Vivado?

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Hello!

 

I am making FPGA design with Artix-7(XC7A200tfbg676-2).

Tool Version is Vivado2013.4.

 

I'd like to use DIFF_TERM.

So I declare and instantiate the IBUFDS as below:

 

IBUFDS_DIFF_OUT #(
.DIFF_TERM ("TRUE"),
.IBUF_LOW_PWR ("FALSE")) 
data_in (
.I (datain_p[i]),
.IB (datain_n[i]),
.O (rx_data_in_p[i]),
.OB (rx_data_in_n[i]));

 

After implementation, I confirmed the IO report.

But I couldn't find DIFF_TERM word and I could find all "NONE" in "System integrity".

I think DIFF_TERM is written in "System integrity" refer to below.

 

http://forums.xilinx.com/t5/Spartan-Family-FPGAs/How-do-I-know-if-DIFF-TERM-is-set-to-be-TRUE-correc...

 

I worry about if DIFF_TERM is set to be TRUE correctly.

 

If you know it , please tell me.

 

Best regards.

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1 Solution

Accepted Solutions
Xilinx Employee
Xilinx Employee
8,127 Views
Registered: ‎06-14-2012

Re: How do I know if DIFF_TERM is set to be TRUE correctly in Vivado?

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You can check the property in properties tab once you open the implemented design. The value should be updated there.

Further its a known issue in 2013.4 and 2014.1 where the IO report doesnt show it.

This will be fixed in 2014.2

Current workarounds are to :

1. Open synthesized/implementation project and check that DIFF_TERM = TRUE has been applied by selecting the expected IO pads and viewing its "Properties" tab.

2. Use the get_property tcl command on the IO pad. 

The example below shows a screenshot of the two ways to check the DIFF_TERM attribute. In this case the attribute were applied to and checked for a DRP clock.

 

View solution in original post

Capture.PNG
5 Replies
Xilinx Employee
Xilinx Employee
8,128 Views
Registered: ‎06-14-2012

Re: How do I know if DIFF_TERM is set to be TRUE correctly in Vivado?

Jump to solution

You can check the property in properties tab once you open the implemented design. The value should be updated there.

Further its a known issue in 2013.4 and 2014.1 where the IO report doesnt show it.

This will be fixed in 2014.2

Current workarounds are to :

1. Open synthesized/implementation project and check that DIFF_TERM = TRUE has been applied by selecting the expected IO pads and viewing its "Properties" tab.

2. Use the get_property tcl command on the IO pad. 

The example below shows a screenshot of the two ways to check the DIFF_TERM attribute. In this case the attribute were applied to and checked for a DRP clock.

 

View solution in original post

Capture.PNG
Advisor pedro_uno
Advisor
6,241 Views
Registered: ‎02-12-2013

Re: How do I know if DIFF_TERM is set to be TRUE correctly in Vivado?

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Siktap

 

Your suggestion, to browse each pin in the Vivado GUI,  is a very arduous way to check something that should be reported automatically in the IO pins report.

 

In ISE there was a column in the IO report that told you what type of termination is applied to each pin. That makes it very easy to scan all your I/O pins to make sure that they are terminated correctly.

 

Vivado also has a IO report and there is a column labled "IN_TERM".  Unfortunately, I have never found any information in that column. All entries are blank.

 

I would consider it a bug in the Vivado software if the default IO report does not list the pin terminations.  Please, can someone at Xilinx take this up.

 

    Pete

----------------------------------------
DSP in hardware and software
-----------------------------------------
Xilinx Employee
Xilinx Employee
6,232 Views
Registered: ‎06-14-2012

Re: How do I know if DIFF_TERM is set to be TRUE correctly in Vivado?

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Hi Pete,

Yes I am in completely agreement with you. This is a known bug as earlier mentioned and devlopment is working on it to make sure that it has all the information needed for a board designer. This will be fixed soon.

 

Regards

Sikta

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Contributor
Contributor
2,028 Views
Registered: ‎05-17-2009

Re: How do I know if DIFF_TERM is set to be TRUE correctly in Vivado?

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Still not in 2018.2, apparently.  This is a bit awkward because the SelectIO IP wizard is setting a .DIFF_TERM("FALSE") attribute on my IBUFDS objects (why?), while the project's top-level .XDC file sets DIFF_TERM to TRUE on those ports.  Had to do a lot of Googling to find out how to check it in Vivado.

Adventurer
Adventurer
1,003 Views
Registered: ‎10-31-2017

Re: How do I know if DIFF_TERM is set to be TRUE correctly in Vivado?

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Not implemented in Vivado 2018.3 yet. Kudos to the hint on get_property command, it was helpful.

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