W89C841F Datasheet, PDF (73/102 Pages) Winbond – 3-IN - 1 10/100M FAST ETHERNET CONTROLLER

W89C841F/D
Dc0/DBRAR Boot ROM Access Register
The register is used to specify the control function and the data message passing for the on board
Boot ROM.
BIT ATTRIBUTE BIT NAME
DESCRIPTION
31
30:28
27
26
R
R/W
R/W
R/W
-
BROMSEL
BROMRD
BROMWR
Reserved. Fixed to 0.
Boot ROM Size Select
BROMSEL bits decides the size of the on board boot ROM
device.
00x = No Boot ROM
010 = 8K
011 = 16K
100 = 32K
101 = 64K
110 = 128K
111 = 256K
Loaded from EEPROM after Power-on reset.
BootROM Read Control
When EESEL bit of register Dc4/DEEAR[31] is reset, setting
this bit will perform the on-board boot ROM read operation
with the reading address specified by bits BROMA. The bit
BROMRD will be cleared automatically after BootROM read
operation is completed. Bit BROMRD will not allow to be set
high, even writing a logic 1 to BROMRD if the bit EESEL is
set.
BootROM Write Control
When EESEL bit of register Dc4/DEEAR[31] is reset, setting
this bit will perform the on-board boot ROM write operation
with the writing address specified by BROMA. This bit
BROMWR will be cleared automatically after BootROM write
operation is completed. The BROMWR will not allow to be
set high, even writing a logic 1 to BROMWR if the bit EESEL
is set.
25:8
R/W
BROMA Boot ROM Offset Address
This field contains boot ROM offset address.
7:0
R/W
BROMD Boot ROM Data
BROMD are used to store the read/write data for the on
board Boot ROM access when EESEL is reset to low.
BROMD is of no meaning if the EESEL is set to high.
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Publication Release Date: October 18, 2001
Revision A3