AnsweredAssumed Answered

MDC MDIO stay low forever after configuring RMII / Ethernet on STM32F4

Question asked by zbrozek.sasha.001 on Aug 31, 2012
Latest reply on Jul 18, 2013 by B3rsui
I'm trying to use RMII between an STM32F407VE and an SMSC LAN8720 PHY. So far I've followed along with the STM32F4 Ethernet example but am having less than stellar success.

As far as I can tell, MDC and MDIO go low after the Ethernet clocks are turned on, but then never rise again. No data appears to be crossing the bus, even though the Ethernet configuration routines (supplied by ST) should be trying to communicate with the PHY.

I've found only one seemingly relevant forum post here. Sadly, its contents did not help me.

Relevant code snippets here and here.

Suggestions for why the lines may be stuck low would be most appreciated. Thank you!