Author Topic: MMCM Not Locking with TE0820 Board using Si5338 with BUFG  (Read 355 times)

Sheshu

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MMCM Not Locking with TE0820 Board using Si5338 with BUFG
« on: October 29, 2020, 12:55:25 PM »
Hi all,

I use TE0820 Board with TE0703 Carrier board.

I face an issue when trying to see on chip signals with ILA.
 
I use an external differential clock (25MHz) which is not connected to GC pin but use IBUFDS and BUFG to connect to an MMCM with constraints set to ignore CLOCK_DEDICATED_ROUTE for this path. The MMCM is configured with Source as "No Buffer".

Here is my constraint: set_property CLOCK_DEDICATED_ROUTE FALSE [get_nets IBUFDS_si_clk25_inst/O]

What I see from the ILA output is that the MMCM doesn't get locked any my design doesn't run.

Do you have some recommendation on how to make it run ?

The reset type is Active High and I use Dynamic Phase shift ports which are pulled low.

The simulation works well.

I also attach the ILA output with this mail.
The input clock is also the source for an upcounter which counts upto 10 in the ILA.
I use the same input clock to sample the locked signal.

Could anyone give me some tips on how to tackle it.


JH

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Re: MMCM Not Locking with TE0820 Board using Si5338 with BUFG
« Reply #1 on: October 29, 2020, 01:34:19 PM »
Hi,
we have a reference design which use SI5338 CLK (prebuilt binaries are included):
https://wiki.trenz-electronic.de/display/PD/TE0820+Test+Board
SI5338 will be initilised with our fsbl.
You can check CLK via Vivado HW Manager:
https://wiki.trenz-electronic.de/display/PD/TE0820+Test+Board#TE0820TestBoard-VivadoHWManager

br
John

Sheshu

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Re: MMCM Not Locking with TE0820 Board using Si5338 with BUFG
« Reply #2 on: October 29, 2020, 01:47:18 PM »
Hello JH,

Thanks for the reply.
I have used the example design from Trenz for booting my board to check clocks etc., everything is good.
The Si5338 clock which is 25MHz is working well as I can count upto 10 with it ( in the ILA).
It is connected to the MMCM input via an IBUFDS and BUFG, currently I don't have an option for other clock for my MMCM.

The issue is the MMCM won't lock, the reset is driven low as in the ILA.
I'm surprised why the MMCM won't lock which works very well in my simulations.

Do you have some tips on how to tackle this?

JH

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Re: MMCM Not Locking with TE0820 Board using Si5338 with BUFG
« Reply #3 on: October 29, 2020, 02:11:21 PM »
where did you see SI CLK 25 MHz?
br
John

Sheshu

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Re: MMCM Not Locking with TE0820 Board using Si5338 with BUFG
« Reply #4 on: October 29, 2020, 02:14:42 PM »
Ok I think I got the issue.
The clock from Si5338 by default is 200Mhz and not 25 MHz.
I will check with ILA again after the required changes.
Thanks

Sheshu

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Re: MMCM Not Locking with TE0820 Board using Si5338 with BUFG
« Reply #5 on: October 29, 2020, 03:33:02 PM »
Thanks, the issue is solved  :)