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Visitor
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Registered: ‎12-22-2018

MMCM Losing Lock on a PYNQ-Z2 (Zynq-7020)

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Hey all, finally got my PYNQ in the mail. I started up a simple project with an MMCM and register just to see if the board works. I seem to be losing lock every 2 seconds or so. I'm only using the PL side of the chip by programming in Vivado. Is the oscillator on the board too jittery to feed into a PLL/MMCM or have I set it up wrong? I can provide my settings and source if needed.

 

Thanks,

Thomas

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Visitor
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Registered: ‎12-22-2018

I've found the fix. The Realtek controller that supplies the clock on this board goes into reset when it doesn't have an ethernet cord plugged in. By plugging in an ethernet cord to the port on the board, the Realtek chip turns on and stays out of reset, keeping the input clock going and the MMCM locked.

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Visitor
Visitor
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Registered: ‎12-22-2018

I've found the fix. The Realtek controller that supplies the clock on this board goes into reset when it doesn't have an ethernet cord plugged in. By plugging in an ethernet cord to the port on the board, the Realtek chip turns on and stays out of reset, keeping the input clock going and the MMCM locked.

View solution in original post

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