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Observer nicolashuger
Observer
173 Views
Registered: ‎02-20-2019

How to use 2 different TX line rates with transceiver wizard ?

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Hi

I try to generate 2 SDI output (HD-SDI and SD SDI) with a quadGTP of Artix7-50

I am using 2 input clock : REFCLK0 and REFCLK1
But there is only 1 TX line rate in "7 series FPGAs Tansceivers Wizard (3.6)"

In "Encoding and Clocking" tab of the wizard I can select the optional port : TXSYSCLKSEL
But this port does not appear in the top of the gtp component generated.

How can I select
REFCLK0 -> PLL0 for TX of GTP_X0Y0
and
REFCLK1 -> PLL1 for TX of GTP_X0Y1 
?

Nicolas

1 Solution

Accepted Solutions
Moderator
Moderator
38 Views
Registered: ‎11-09-2015

Re: How to use 2 different TX line rates with transceiver wizard ?

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HI @nicolashuger 

You might need to use 2 GT wizards to share the reference clock between the tranceiver (one with include logic in the core the other include in the example design), sharing the GT common between the cores.

There is only a factor 2 between the 2 line rate so I believe a single reference clock is fine. You just have to configure the txrate in differently between the traceivers


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
4 Replies
Moderator
Moderator
116 Views
Registered: ‎11-09-2015

Re: How to use 2 different TX line rates with transceiver wizard ?

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Hi @nicolashuger 

If I understand correctly, you are trying to send at the same time 1 HD-SDI output on one traceiver and one SD-SDI ouput on another tranceiver of the same quad. Is it correct?

First thing I want to say is that you might want to spend some time reading deeply the following application note. It would give you indestanding on how to implement SDI interfaces on Artix GTPs:

xapp1097 - Implementing SMPTE SDI Interfaces with Artix-7 FPGA GTP Transceivers

Looking at this xapp you could see that using the 2 different PLLs for 2 different tranceivers is covered:

 

xapp.JPG

WIth that said, if you are using only a single rate (integer (/1) or fractional (/1.001)), you should be able to use a single reference clock for the 2 tranceivers, configuring only the dividers individually for each tranceiver.

Regards

 

 


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
Observer nicolashuger
Observer
66 Views
Registered: ‎02-20-2019

Re: How to use 2 different TX line rates with transceiver wizard ?

Jump to solution

Hi @florentw 

Thank you for your answer.

Yes  I try to send at the same time 1 HD-SDI output on one traceiver and one SD-SDI ouput on another tranceiver of the same quad.

I read the xapp 1097 and you are right : what I want to do is the configuration of Figure 5. However I can not configure it with the wizard of vivado since there is only one TX clock source.

I can configure the quad by changing the code generated by the wizard. I have to change : TXSYSCLKSEL for the GTPE2_CHANNEL of the GTP which have to use the other clock source. (+TXOUTCLKSEL and others signals for ref_clock...)

It is working for my configuration but I am not able to do it with the GTP wizard.

 

Concerning the single clock, I think I can not use it since the 2 PLL are not working in the same configuration :

for HD_SDI I use 148.35MHz as input clock and the PLL generate 1.4835GHz for out and 74.17 for usr_clock

for SD_SDI I use 148.5MHz as input clock and the PLL generate 2.97GHz for out and 148.5 for usr_clock
(SD is generated like 3G-SDI with a 2/11 clock enable to realise 270Mbit/s from 2.97Gbit/s)

Then even if the input clock ratio is 1/1.001 I think I can not use only one... but maybe I am wrong ? 

 

Regards

Nicolas

 

0 Kudos
Moderator
Moderator
39 Views
Registered: ‎11-09-2015

Re: How to use 2 different TX line rates with transceiver wizard ?

Jump to solution

HI @nicolashuger 

You might need to use 2 GT wizards to share the reference clock between the tranceiver (one with include logic in the core the other include in the example design), sharing the GT common between the cores.

There is only a factor 2 between the 2 line rate so I believe a single reference clock is fine. You just have to configure the txrate in differently between the traceivers


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
Observer nicolashuger
Observer
31 Views
Registered: ‎02-20-2019

Re: How to use 2 different TX line rates with transceiver wizard ?

Jump to solution

Hi @florentw 

Thank you for the answer, I will try it.

Regards

Nicolas

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