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AM3358: Unstable PHY detection

Part Number: AM3358

Hi.

I used CPSW enet_echo example from starterkit and mentioned, that sometimes example failed to detect PHY.

Basically, after MDIO setup MDIOALIVE content is 0x0, and example finishes with error

"No PHY found at address ..."

Also, I have discovered that this problem reproduces more often if I change MDIO_FREQ_OUTPUT to higher values.

If I change MDIO_FREQ_OUTPUT from 1 Mhz to 10 Mhz the problem reproduces every time.

Are there a kind of platform limitation to this frequency? Or maybe i misunderstood something, tell me please...

thank you.

  • The maximum MDIO clock frequency for AM335x devices is 2.5MHz. This is clearly stated in the AM335x Datasheet, Rev. J section 7.6.1.1. Normally 400 to 500kHz is used on this device. You should also check what MDIO clock frequency the PHY is capable to support.