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Visitor kgdqqfgesky3
Visitor
1,236 Views
Registered: ‎10-15-2016

How can i measure ZC706 si5324 clock with oscilloscope

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Hi everyone! I'm trying to do the CPRI loopback test with SFP GTX on ZC706 board.I don't have any differential clock source,so I want to use the clock generated by si5324.In order to measure the si5324 output clock,I connect the PIN AC7/AC8 (wire to SI5324_out_n/p on zc706board) to an IBUFGDS  I/IB.Then I connect the output of IBUFGDS to OBUFDS Input port.Finally I connect the OBUFDS diff_p/n output to PIN AD18/AD19 (SMA_USR_CLK) so I can measure them easily.

 

But the vivado implementation get critical warning:Cannot set LOC property of ports,Could not legally place instance IBUFGDS at AC8(IPAD_X1Y40) since it belongs to a shape containing instance sys_clk_n.The shape requires relative placement between IBUFGDS inst and sys_clk_n that cannot be honoured because it would result in an invalid location for sys_clk_n.

write bitstream also has rule violation error:Unspecified I/O standard sys_clk_n,sys_clk_p.in the I/O Pin page,I try to set sys_clk_n/p to AC8 but it turns out "invalid ports" and so on.That means I could not place clock on PIN AC7/8 .

 

PIN AC7/8 belong to GTXREFCLK and I connect them to IBUFGDS instance,could this be the reason of error?If so,what can I do to connect the si5324 output clock to  measurable SMA ports?

Thank you

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Xilinx Employee
Xilinx Employee
1,855 Views
Registered: ‎06-02-2017

Re: How can i measure ZC706 si5324 clock with oscilloscope

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Hi @kgdqqfgesky3,

 

As you mentioned, AC7/8 is dedicated pins for GT reference clock, so you cannot route the clock into them like general IO.

Please refer to UG476, Figure 3-28. If you want to use the GT reference clock to fabric, you must use the IBUFDS_GTE2 primitive as below screenshot.

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Scholar hbucher
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1,227 Views
Registered: ‎03-22-2016

Re: How can i measure ZC706 si5324 clock with oscilloscope

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@kgdqqfgesky3  Why dont' you use the Si5324 to feed a binary counter then slice it into the LEDs? 26:28 would give you a period of 4.64 seconds 

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Visitor kgdqqfgesky3
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1,196 Views
Registered: ‎10-15-2016

Re: How can i measure ZC706 si5324 clock with oscilloscope

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Hi,thanks for your apply.But the problem is I can't get the si5324 output clock into FPGA,because the place PIN error.

1.png2.png

As you see in the ZC706 schematic,the si5324 output have been connect to ZYNQ PIN AC7/8.But when I place clock input on AC7/8,I got error message.So I can't drive the LED with si5324 output clock source.

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Xilinx Employee
Xilinx Employee
1,856 Views
Registered: ‎06-02-2017

Re: How can i measure ZC706 si5324 clock with oscilloscope

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Hi @kgdqqfgesky3,

 

As you mentioned, AC7/8 is dedicated pins for GT reference clock, so you cannot route the clock into them like general IO.

Please refer to UG476, Figure 3-28. If you want to use the GT reference clock to fabric, you must use the IBUFDS_GTE2 primitive as below screenshot.

-------------------------------------------------------------------------------------------------------------------------------------------
Kindly note- Please mark the Answer as "Accept as solution" if information provided is helpful.

Give Kudos to a post which you think is helpful and reply oriented.
--------------------------------------------------------------------------------------------------------------------------------------------

 

-------------------------------------------------------------------------------------------------------------------------------------------
Kindly note- Please mark the Answer as "Accept as solution" if information provided is helpful.

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Visitor kgdqqfgesky3
Visitor
1,153 Views
Registered: ‎10-15-2016

Re: How can i measure ZC706 si5324 clock with oscilloscope

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Thanks a lot!Your solution really works.I use ibufds_gte2-->BUFG-->ODDR-->OBUFDS primitives,the output of OBUFDS connect to SMA ports.No more errors.After program si5324 via PS_IIC,I can see the 125M Clock in the oscilloscope.

 

The design resource of Rdf0217-vc707-si5324 is really helpful.Attached file "gtxe2_top" is a reference for those who  have the same problem.

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