LAN83C175 Datasheet, PDF (35/92 Pages) SMSC Corporation – Ethernet CARDBUS Integrated Controller With Modem Support

CONFIGURATION
The LAN83C175 is automatically configured by
the host system power-up software before the
machine is booted to an operating system.
Configuration is performed through the CardBus
configuration space. The LAN83C175 indicates
its requirements and the power-up software
allocates the appropriate resources. Note that
there is a separate configuration space for the
ethernet function and the modem function.
The LAN83C175 has the following requirements
for both the ethernet and modem functions:
A) 256 byte I/O space (may be mapped
anywhere in 32-bit I/O address space)
B) 4 Kbyte memory space (may be mapped
anywhere in 32-bit host memory space -
may be disabled on any host with I/O
space).
C) 64 Kbyte expansion ROM space (may be
mapped anywhere in 32-bit host memory
space - will be disabled after boot
sequence).
D) Interrupt hardwired to CardBus nINTA line.
Because resources are relocatable, device
drivers must read the configuration registers
after boot time to determine where the device is
mapped.
Mapping of ROM and Control Functions
The LAN83C175 control registers are mapped
into both host I/O and memory space (to
accommodate host systems with no I/O space).
In machines with I/O space, mapping into
memory address space may optionally be
disabled by a bit in EEPROM. Any change in
the memory map enable bit will not take effect
until the system is reset (hard reset). The I/O
base address for the control registers will be
stored in the I/O Base Address Register (10h in
the configuration space). The memory base
address for the control registers will be stored in
the Memory Base Address Register (14h in the
configuration space). The I/O space is 256 bytes
long and is always naturally aligned. When
mapped into memory, the control registers
consume 4 Kbytes, even though only the first
256 bytes are used. They are always aligned to
a 4 Kbyte boundary. Access to the control
registers is enabled by the memory space and
I/O space enable bits in the CardBus Command
Register (04h in the configuration space). Both
memory space and I/O space will be disabled
after reset. All control registers are dword
accessible only.
The expansion ROM is accessible when the
"address decode enable" bit in the ROM base
address register (30h in the configuration space)
is set and the memory space enable bit is set.
The ROM code is not executable in place. It
must be copied into system RAM and executed
from RAM (as per CardBus specification).
LAN83C175 control functions will not be
accessible through memory address space
while the ROM address decode enable bit is
set. Note that this ROM also contains the CIS
information for both the ethernet and modem
function.
When the expansion ROM is read, the
LAN83C175 will always return all four bytes in
the dword being accessed, regardless of which
byte enables are active.
The LAN83C175 will write to the flash ROM on a
byte basis, as decoded by the byte enables.
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