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
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
| EEPROM WORD |
REGISTER | ADDRESS |
Configuration | IOS Value * 4 |
Register |
|
Base Register | (IOS Value *4) + 1 |
|
|
INDIVIDUAL ADDRESS
If
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
On EEPROM write operations (after setting the
STORE bit) the values of the CONFIGURATION REGISTER and BASE
100