[En-Nut-Discussion] Ethernut newbie with a lot of questions

[Tim Tait]

Greg Wood wrote:
> likely be an ethernut compatible setup.  I want to avoid having to go
> radio->magnetics->switch<-magenets<-ethernut.  It seems to me that if
> everything will be build onto a PCB there is no need for magnetics.  Is
> there a chipset that implements a simple 4 or 5 port 10mbps switch that
> would allow me to avoid the magnetics for the devices that are on the
> pcb together, and also build the switch onto the PCB?
>  

Most phy's do not work at 10Mbit without a transformer due to the driver 
ciruit topology and levels required, but 100Mbit should work with 
capacitor coupling. Unfortunately autonegotiaton is done at 10Mbs, so it 
would be required to force the link speed/duplex on both sides.

It should also be possbile to use a single transformer to accomplish the 
interface.

If you have access the the MAC/PHY interface from the MAC, (MII, RMII or 
whatever), and the Switch uses the same interface PHY type, it is 
usually possible simply to flip the interface and wire the MAC to Switch 
directly. If the Switch or MAC has integrated phy's and doesn't allow 
direct access to that interface, this of course won't be possible.


Tim