SMC91C100 Datasheet, PDF (59/83 Pages) List of Unclassifed Manufacturers – FEAST Fast Ethernet Controller

BOARD SETUP INFORMATION
The following parameters are obtained from the
EEPROM as board setup information:
ETHERNET INDIVIDUAL ADDRESS
I/O BASE ADDRESS
10BASE-T or AUI INTERFACE
MII or ENDEC INTERFACE
INTERRUPT LINE SELECTION
REGISTER
Configuration
Register
Base Register
EEPROM WORD
ADDRESS
IOS Value * 4
(IOS Value * 4) + 1
All the above mentioned values are read from the
EEPROM upon hardware reset. Except for the
INDIVIDUAL ADDRESS, the value of the IOS
switches determines the offset within the EEPROM
for these parameters, in such a way that many
identical boards can be plugged into the same
system by just changing the IOS jumpers.
INDIVIDUAL ADDRESS
20-22 hex
If IOS2-0 = 7 , only the INDIVIDUAL ADDRESS is
read from the EEPROM. Currently assigned values
are assumed for the other registers. These values
are default if the EEPROM read operation follows
hardware reset.
In order to support a software utility based
installation, even if the EEPROM was never
programmed, the EEPROM can be written using
the SMC91C100. One of the IOS combination is
associated with a fixed default value for the key
parameters (I/O BASE, INTERRUPT) that can
always be used regardless of the EEPROM based
value being programmed. This value will be used if
all IOS pins are left open or pulled high.
The EEPROM is arranged as a 64 x 16 array. The
specific target device is the 9346 1024-bit Serial
EEPROM. All EEPROM accesses are done in
words. All EEPROM addresses in the spec are
specified as word addresses.
The EEPROM SELECT bit is used to determine the
type of EEPROM operation: a) normal or b) general
purpose register.
a) NORMAL EEPROM OPERATION - EEPROM
SELECT bit = 0
On EEPROM read operations (after reset or after
setting RELOAD high) the CONFIGURATION
REGISTER and BASE REGISTER are updated
with the EEPROM values at locations defined by the
IOS2-0 pins. The INDIVIDUAL ADDRESS registers
are updated with the values stored in the
INDIVIDUAL ADDRESS area of the EEPROM.
59