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imx7d fec0 AD8031 - no external 125MHz clock

Question asked by Edward Tyrrell on Apr 8, 2019
Latest reply on Apr 16, 2019 by Edward Tyrrell

Quick question about the AD8031 in RGMII mode and it providing a 125MHz clock to the SOC. The AD8031 MDIO side works fine, but I can never get a good link status. I suspect it might be clock management. By default the driver selects an external 125MHz clock from the AR8031, seen in setting up the SOC clocks and poking the AR8031 registers. On my custom board I never see the 125MHz clock exiting the AR8031 ( I can get the AR8031 default 25MHz clock if I tweak the code ). Question is, is this clock there all the time or only produced once the link is up and the AD8031 can derive it off the LAN?

 

Thanks.   

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