LAN83C175 Datasheet, PDF (26/92 Pages) SMSC Corporation – Ethernet CARDBUS Integrated Controller With Modem Support

In order to comply with the CardBus
specification, the LAN83C175 will not swap the
data bytes on reads or writes to the
configuration or control register space. The
software driver will be responsible for correctly
interpreting the bytes when performing 32 bit
register read or writes on a Big Endian
machine.
When reading or writing Ethernet packet data,
the LAN83C175 will not perform any byte
swapping internally because the data on the
CardBus bus will already be in the correct order.
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