w89c840af Winbond Electronics Corp America, w89c840af Datasheet - Page 26

• Manufacturer Part Number: w89c840af
• Description: 100/10mbps Ethernet Controller
• Manufacturer: Winbond Electronics Corp America

configuration data and store these data into the configuration registers and the control register of the
W89C840AF after hardware reset. The serial EEPROM 93C06 or 93C46 will be the choice as the storage
device for storing these configuration data.
The C24/CMIIR register provides an alternative path to access the data in EEPROM. The bits 0, 1, 2, ... and 7
of CMIIR are general I/O port. When the bit 11 of CMIIR is set to high, the bits 0, 1 and 2 will be put on the
EECS, BtAdata1/EECK, and BtAdata2/EEDI, respectively , to trigger EEPROM. The data from EEPROM
running over the pin BtAdata3/EEDO will be hold and latched by the bit 3 of CMIIR, and be read by
W89C840AF. The application program can program bits 0, 1 and 2 of CMIIR to generate the chip select
signal, clock and read command, based on the AC timing spec. of the EEPROM device, to EEPROM, and
running over the pins EECS, BtAdata1/EECK, and BtAdata2/EEDI respectively. For reading the output data
from EEPROM, the application program should make the necessary level transition as a clock on
BtAdata1/EECK. One falling edge will trigger the EEPROM device to drive the next bit of output data
relative to the input command.
program can write data into the EEPROM through programming the bits 0, 1 and 2 of the register CMIIR. In
the write cycle of the EEPROM device, the data on BtAdata3/EEDO is meaningless.
BOOT ROM system read and software programming function
on-board boot ROM device will be mapped into the host memory by the system BIOS (Basic Input/Output
System). After power-on reset, The BIOS will write a set of value with all 1 to the F30/FERBA configuration
register and then read the value back. The W89C840AF will return the all 1 value, except some bits with 0,
Address
09H~3FH
08H
07H
06H
05H
04H
03H
02H
01H
00H
The data mapping and its offset address for all of the above parameters is as the following table.
The W89C840AF will generate a nine-word reading command to the EEPROM to read the
Other than the reading after hardware reset, the EEPROM can be read by the application program.
The EEPROM can be programmed through the general I/O port of the W89C840AF. The application
The W89C840AF can address up to 256 Kbytes memory space for the on-board boot ROM device. The
High Byte (BIT 15 ~ BIT 8)
reserved
PMCSP/RWUL/C48
Vendor ID(high byte)
Device ID(high byte)
Subsystem Vendor ID(high byte)
Subsystem ID(high byte)
MAXLAT
Ethernet Address 5
Ethernet Address 3
Ethernet Address 1
-26 -
Low Byte (BIT 7 ~ BIT 0)
reserved
Revision ID
Vendor ID(low byte)
Device ID(low byte)
Subsystem Vendor ID(low byte)
Subsystem ID(Low byte)
MINGNT
Ethernet Address 4
Ethernet Address 2
Ethernet Address 0
Publication Release Date:October 2000
Revision 1.01
W89C840AF