BOARD SETUP INFORMATION

ISA MODE

The following parameters are obtained from the EEPROM as board setup information:

ETHERNET INDIVIDUAL ADDRESS I/O BASE ADDRESS

ROM BASE ADDRESS 8/16 BIT ADAPTER 10BASE-T or AUI INTERFACE INTERRUPT LINE SELECTION

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 SMC91C95. One of the IOS combination is associated with a fixed default value for the key parameters (I/O BASE, ROM 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 shown are specified as word addresses.

 

EEPROM WORD

REGISTER

ADDRESS

Configuration

IOS Value * 4

Register

 

Base Register

(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.

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.

On EEPROM write operations (after setting the

STORE bit) the values of the CONFIGURATION REGISTER and BASE

100

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SMC Networks SMC91C95 manual Board Setup Information ISA Mode, Ethernet Individual Address I/O Base Address, Eeprom Word