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Observer gianmarcoborri
Observer
1,087 Views
Registered: ‎11-14-2017

GTX Reference Clock ZC706

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Hello all,

I've got a ZC706 Xilinx Evaluation Board and I am trying to set up GTX into Zynq-7000 FPGA.

To make it work I need to provide a reference clock for this transceiver. I have already read a lot of tutorials and threads on this forum but now I am only confused. I understood this:

 

1) GTX transceiver has 4 independent banks and 2 independent refclock each bank (MGT_REFCLK)

2) Possible refclocks are: 1 => FMC HPC D4/D5 (HPC_GBTCLK0)

                                         2 => FMC HPC B20/B21 (HPC_GBTCLK1)

                                         3 => FMC LPC D4/D5 (LPC_GBTCLK0)

                                         4 => SMAs

                                         5 => SI5324

3) All MGT_REFCLK have on the path a bypass capacitor

4) I cant use other external clocks for this purpose like integrated chip Si570 (USRCLK_P/N). Ok, there is a n-th possibility: internal FPGA clock for test only...i dont want to use it.

 

Am I right? Mostly for *4*

 

 

Thanks for helping

 

Gianmarco Borri

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1 Solution

Accepted Solutions
Scholar jmcclusk
Scholar
1,077 Views
Registered: ‎02-24-2014

Re: GTX Reference Clock ZC706

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Using an internal clock as a reference can work, but at the cost of greatly increased phase noise and reduced eye margins.  It's always better to use a clean external reference.   The SI5324 will give you a nice clean clock,  you just have to program the frequency you want.

Don't forget to close a thread when possible by accepting a post as a solution.
5 Replies
Scholar jmcclusk
Scholar
1,078 Views
Registered: ‎02-24-2014

Re: GTX Reference Clock ZC706

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Using an internal clock as a reference can work, but at the cost of greatly increased phase noise and reduced eye margins.  It's always better to use a clean external reference.   The SI5324 will give you a nice clean clock,  you just have to program the frequency you want.

Don't forget to close a thread when possible by accepting a post as a solution.
Observer gianmarcoborri
Observer
1,027 Views
Registered: ‎11-14-2017

Re: GTX Reference Clock ZC706

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Hi jmcclusk,

thanks for the quick reply. After some work with software and I2C I've finally set up SI5324. This chip works perfectly!

Regards

 

Gianmarco Borri

 

Observer thanhdokt89
Observer
743 Views
Registered: ‎12-08-2015

Re: GTX Reference Clock ZC706

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Dear @gianmarcoborri,

Now, I'm working on setting to use clock from SI5324 on ZC706, but I am facing some issues with SDK software.

Could you please share the Project design and the SDK to set up SI5324 via my email: tienthanhkt09@gmail.com ?

Thank in advance!

Best regrds,
Thanh Do
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Observer thanhdokt89
Observer
686 Views
Registered: ‎12-08-2015

Re: GTX Reference Clock ZC706

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Dear @gianmarcoborri,

 

Could you pls share the hardware and the software to set up for SI5324 via my email: tienthanhkt09@gmail.com?

 

Thanks in advance!

 

Best regards,

Thanh Do

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Adventurer
Adventurer
655 Views
Registered: ‎05-25-2016

Re: GTX Reference Clock ZC706

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A SI5324 driver source file named 'xiicps_si5324_intr_example.c' was included in 'rdf0240-zc706-bist-c-2015-1'.
It's quite easy to set up SI5324 using 'xiicps_si5324_intr_example.c'
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