SJA1105 xMII Connection

[harish720]

As shown below, in the typical application circuit of SJA1105 ethernet switch IC, I have noticed that a host processor is always connected to one of the xMII ports of the switch and also through an SPI channel. According to the datasheet, the switch IC can be configured through the SPI communication, so why do we need to use up one of the ports to connect to the host processor? Why not use it for another incoming ethernet connection? What advantages do connecting the host processor through xMII interface give us?

[PetrS · Accepted solution]

Hi,

a DS mentions that briefly...

Ethernet connectivity to the host processor is only needed if the system has to support AVB operation or other bridge management protocols such as STP/RSTP. If such operations are not needed, all the
ports can be used for data traffic.

BR, Petr

[harish720]

Hi,
Thanks for the response.
Just one more doubt, this an automotive grade switch and can be used for GBASE-T1 (single pair ethernet) but if we use an appropriate PHY then we can also use it with full GBASE-T (using all 4 pairs of ethernet) cable for communication right?

[PetrS]

Hi,

I think so

BR, Petr

[harish720]

Thanks for your support Petr.