PC87413 datasheet(83/257 Pages) NSC

83 / 257 page

3.0 Device Architecture and Configuration (Continued)

Revision 1.2

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3.15.11 X-Bus Memory Configuration Register 1 (XMEMCNF1)

This register is reset by hardware to 00h.

Power Well:VSB

Location:Index F7h

Type:

R/W or RO

Bit

76543210

Name

FWHID

BIOFWHEN UDMEMEN BIOEXTEN BIOLPCEN

Reset

0000

Strap

Bit

Description

7-4

FWHID (BIOS FWH ID). These four bits correspond to the Device Select nibble that is part of a FWH transaction

(see Section 4.2 on page 90 for details).

BIOFWHEN (BIOS FWH Enable). When set, this bit enables the PC8741x device to respond to LPC-FWH

transactions to the BIOS-FWH space. The default value is set according to the XCNF2 strap, sampled at VSB

Power-Up reset. The value of this bit is later updated based on the detected host BIOS scheme (see Section

3.15.3 on page 76 for details).

0: Disabled (default when XCNF2 = 0 - disables BIOS configuration)

1: Enabled (default when XCNF2 = 1 - enables BIOS configuration)

UDMEMEN (User-Defined Memory Space Enable). When set, this bit enables the PC8741x device to respond

to LPC memory read and write transactions in the user-deﬁned memory range. The base address and size of

the user-deﬁned range is speciﬁed by the XMEMBAH/XMEMBAL and XMEMSIZE registers, respectively.

0: Disabled (default)

1: Enabled

BIOEXTEN (BIOS Extended Space Enable). Expands the BIOS address space to which the PC8741x device

responds, to include the Extended BIOS address range.

0: Disabled (default)

1: Enabled

BIOLPCEN (BIOS LPC Enable). Enables the PC8741x device to respond to LPC memory transactions to the

BIOS-LPC space. The default value is set according to the XCNF2 strap, sampled at VSB Power-Up reset. The

value of this bit is later updated, based on the detected host BIOS scheme (see Section 3.15.3 on page 76 for

details).

0: Disabled (default when XCNF2 = 0 - disables BIOS configuration)

1: Enabled (default when XCNF2 = 1 - enables BIOS configuration)

PC87413 Datenblatt(PDF) 83 Page - National Semiconductor (TI)

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