10/100 Non-PCI Ethernet Single Chip MAC + PHY
Datasheet
Chapter 11 Board Setup Information
The following parameters are obtained from the EEPROM as board setup information:
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ETHERNET INDIVIDUAL ADDRESS
I/O BASE ADDRESS
MII INTERFACE
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.
In order to support a software utility based installation, even if the EEPROM was never programmed,
the EEPROM can be written using the LAN91C111. One of the IOS combination is associated with a
fixed default value for the key parameters (I/O BASE) 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.
REGISTER
Configuration Register
Base Register
EEPROM WORD ADDRESS
IOS Value * 4
(IOS Value * 4) + 1
INDIVIDUAL ADDRESS 20-22 hex
If IOS2-IOS0 = 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.
The EEPROM SELECT bit is used to determine the type of EEPROM operation: a) normal or b)
general purpose register.
1. 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.
On EEPROM write operations (after setting the STORE bit) the values of the CONFIGURATION
REGISTER and BASE REGISTER are written in the EEPROM locations defined by the IOS2-IOS0
pins.
The three least significant bits of the CONTROL REGISTER (EEPROM SELECT, RELOAD and
STORE) are used to control the EEPROM. Their values are not stored nor loaded from the EEPROM.
2. GENERAL PURPOSE REGISTER - EEPROM SELECT bit = 1
On EEPROM read operations (after setting RELOAD high) the EEPROM word address defined by the
POINTER REGISTER 6 least significant bits is read into the GENERAL PURPOSE REGISTER.
On EEPROM write operations (after setting the STORE bit) the value of the GENERAL PURPOSE
REGISTER is written at the EEPROM word address defined by the POINTER REGISTER 6 least
significant bits.
RELOAD and STORE are set by the user to initiate read and write operations respectively. Polling the
value until read low is used to determine completion. When an EEPROM access is in progress the
SMSC LAN91C111-REV B
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Revision 1.8 (07-13-05)
DATASHEET
SMSC [ SMSC CORPORATION ]
