Digi NS9750 User Manual

Page 438

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A b o u t t h e P C I - t o - A H B B r i d g e

4 1 4

N S 9 7 5 0 H a r d w a r e R e f e r e n c e

PCI Vendor ID register

Read-only value. To change this value, use the

VENDOR_ID

field in the PCI

Configuration 0 register in the PCI arbiter (see page 428).

PCI Device ID register

Read-only value. To change this value, use the

DEVICE_ID

field in the PCI

Configuration 0 register in the PCI arbiter (see page 428).

PCI Command register

The default value of this register is

0x0000

. Table 255 describes the register fields.

1

These entries are standard read-only PCI configuration registers that are initialized using registers
in the PCI arbiter (see "PCI bus arbiter," beginning on page 418).

Bits

Description

Type

D15:10

Reserved

Hardwired to 0

D09

Fast back-to-back

Hardwired to 0; the device cannot generate
fast back-to-back cycles.

D08

SERR# R/W

D07

Address stepping

Hardwired to 0

D06

Parity error response

R/W

D05

VGA palette snooping

Hardwired to 0

D04

Master MWI (set to 0 for NS9750)

R/W

D03

Special cycle response

Hardwired to 0

D02

Bus master (set to 1 for NS9750)

R/W

D01

Memory enable (set to 1 for NS9750)

R/W

D00

IO enable (set to 0 for NS9750)

R/W

Table 255: Command register

Register
number

[31:24]

[23:16]

[15:08]

[07:00]

Table 254: PCI/bridge configuration registers

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