Kontron KTAM3874-pITX - Manual (Page 33)

KTD-S0057-I Page 29 Ethernet Switch
KTAM3874/pITX Software Guide
7 Ethernet Switch
TI ® 's AM3874 SoC knows two different Ethernet operating modes: the normal dual port and the optional
three port switch setting. The switch contains one port with internal connection and two ports which are
brought out externally on connector J1600 respectively J1601. You can choose between both modes with
an additional U-Boot environment variable (default: dual port mode if the variable is absent).
dual_emac=0 $ Three port switch mode
dual_emac=1 $ Dual port mode
The environment argument default_bootargs represents a good place for attachment with the U-Boot
command editenv . Do not forget to save this setting using the command saveenv .
The following picture shows an example with three boards which have at least one free port. There is no
difference between the connectors J1600 and J1601.
For detection of the actual mode use the command ifconfig within Linux ® . As a result for switch mode you
see only eth0 and for dual port mode eth0 / eth1 .
There are no restrictions regarding the connection of other computer boards for example an x86 board with
the Windows
® operating system.