82374EB datasheet(39/208 Pages) INTEL

39 / 208 page

82374EB82374SB

315 BIOSCSBBIOS CHIP SELECT B REGISTER

Address Offset

43h

Default Value

00h

Attribute

ReadWrite

Size

8 Bits

The LBIOSCS

signal is used to decode access to the motherboard BIOS The ESC decodes memory access

to the following address ranges and if the range has been enabled the LBIOSCS

signal is always asserted

for memory reads in the enabled BIOS range If the BIOS Write Enable bit is set in the configuration register

BIOSCSB the LBIOSCS

is also asserted for memory write cycles

Bit

Description

Reserved

BIOS Write Enable

When enabled LBIOSCS

is asserted for memory read AND write cycles for

addresses in the decoded and enabled BIOS range otherwise LBIOSCS

is asserted for memory

read cycles ONLY

16 Meg BIOS

During Memory access to locations FF0000h – FFFFFFh with this bit set LBIOSCS

will be asserted for memory read cycles If bit 3 of BIOSCSB is set then LBIOSCS

will be asserted

for write cycles as well

High VGA BIOS

During Memory access to locations 0C4000h – 0C7FFFh with this bit set LBIOSCS

will be asserted for memory read cycles If bit 3 of BIOSCSB is set then LBIOSCS

will be asserted

for write cycles as well

Low VGA BIOS

During Memory access to locations 0C0000h – 0C3FFFh with this bit set LBIOSCS

will be asserted for memory read cycles If bit 3 of BIOSCSB is set then LBIOSCS

will be asserted

for write cycles as well

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