W89C841F Datasheet, PDF (30/102 Pages) Winbond – 3-IN - 1 10/100M FAST ETHERNET CONTROLLER

W89C841F/D
Dc4/DEEAR register is used as an interface to access the data between the system and EEPROM.
The following table lists the reading and writing steps for EEPROM.
COMMAND
EEPROM Read
Disable EEPROM
Write Protection
EEPROM Write
Enable EEPROM
Write Protection
STEP
Set EEPROM access bit EESEL to 1.
Set EEPROM offset address to bits EEOA
Set EEPROM Read command to bit EERW
Set Start EEPROM Read/write command to bit StartEERW
Waiting for read operation completed until bit StartEERW change to 0.
Read data from bits EEData.
Set EEPROM access bit EESEL to 1.
Set EEPROM write protection disable command to bit EERW
Set Start EEPROM Read/write command to bit StartEERW
Waiting for write protection disable operation completed until bit StartEERW
change to 0.
1) Set EEPROM access bit EESEL to 1.
2) Set EEPROM offset address to bits EEOA
3) Set EEPROM Data to bits EEData
4) Set EEPROM write command to bit EERW
5) Set Start EEPROM Read/write command to bit StartEERW
6) Waiting for write operation completed until bit StartEERW change to 0.
Set EEPROM access bit EESEL to 1.
Set EEPROM write protection enable command to bit EERW
Set Star EEPROM Read/Write command to bit StartEERW.
Waiting for bit StartEERW change to 0.
BootROM Read and Flash Programming Function
W89C841F can address up to 256 Kbytes memory space for the on-board BootROM or Flash memory
device. The on-board BootROM device will be mapped into the host memory by the system BIOS.
W89C841F will return the mapped memory address depending on the field BootROM size select of
register Dc0/DBRAR[30:28]. This field is loaded from EEPROM after power on reset. The relationship
between the return value from the register F30/FERBA and the field BootROM size select of register
Dc0/DBRAR[30:28] is listed as the following table.
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