Which PHY connection to use on MPC8541...

Gerhard Jaeger g.jaeger at sysgo.com
Tue Oct 11 20:13:39 EST 2005


Hi list,

we're currently designing a custon MPC8541 based board having three ethernet connections.
For some reasons, we'd like to use the FCC1 and 2 + TSEC1. From what I see from the
docs, it should be no problem to connect i.e. a quad phy (for FCC1/2) and a gigabit phy
(for TSEC1) to the EC_MDIO of the TSEC as long as they have different addresses. 
I don't want to use the GPIO stuff for MDIO.

The question is, what does this mean to the drivers? For the gianfar driver this should
be okay and from what I see, the upcoming fs_enet driver supports also a phy 
connected either to the GPIOs (bitbanging) or the TSEC MDIO. Is this right, or am I
missing something essential? 
Would it be better to use the GPIO-MDIO for the FCC phy and the TSEC-MDIO 
for the TSEC phy?

TIA
Gerhard




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