w83626f Winbond Electronics Corp America, w83626f Datasheet - Page 11

• Manufacturer Part Number: w83626f
• Description: Lpc To Isa Bridge Set
• Manufacturer: Winbond Electronics Corp America

6. CONFIGURATION REGISTER
6.1 1 Chip (Global) Control Register
Enable the following configuration registers by writing 26h to the location 4Eh twice.
Change the location to 2Eh by setting bit4 of CR03 or power-on strapping with a
pulled-down register on pin 128.
CR03 (ROM Decoder Register, Default, 100011s0b)
Bit 7-5
Bit4
Bit 3-2
Bit 1
Bit 0
Reserved.
Configure Address and Value
= 0 Write 26h to the location 4E twice. (4Eh and 4Fh are index and data port)
= 1 Write 26h to the location 2E twice (By DACK6 power-on setting with weak pull-down
BIOS Decode Range of High Memory.
= 00 1MB BIOS ROM positive decode.
= 01 2MB BIOS ROM positive decode.
= 10 4MB BIOS ROM positive decode.
= 11 8MB BIOS ROM positive decode. (Default setting)
BIOS ROM decoder Enable.
= 0 Disable BIOS ROM decoder. (Default setting)
=1 Enable BIOS ROM decoder.
BIOS Protected Mode.
=0 BIOS Write Disable. (Default setting)
=1 BIOS Write Enable.
This bit set to “1” for updated BIOS used allow Memory R/W to the range
of BIOS decoded. This bit is always set to “0“ after reset.
resistor).(The pair are 2Eh and 2Fh)
W83626F/W83626D/W83626G
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Publication Release Date: May 25, 2005
Revision A1