Serious flaws with the Gigabit Ethernet PHYs

ArrowElectronics / Agilex-5

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Open Bcuzeau opened 2 days ago

Bcuzeau commented 2 days ago

There are many serious flaws with the Gigabit Ethernet PHYs :-(

The choice of RGMII is dubious,
the default (bootstrap) mode is not good,
and, incredibly, one PHY is clocked... by the other one ! (which by default issues a 12.5MHz instead of 25M !) (to spare a 0.25€ Crystal ?) Don't count on them to synchronize automatically even with no design loaded, as they normally should.

Bcuzeau commented 10 hours ago

And the 1st PHY (generating the incorrect clock) is on the HPS side so mitigation goes thru FSBL patching...