Register Description

R

3.6.3PCICMD1—PCI-PCI Command Register (Device 1)

Address Offset:

04–05h

Default:

 

0000h

Access:

 

RO, R/W

Size

 

16 bits

 

 

 

Bit

 

Descriptions

 

 

 

15:10

Reserved.

 

 

 

9

Fast Back-to-Back(FB2B)—RO.Not Implemented; Hardwired to 0.

 

 

8

SERR Message Enable (SERRE1)—R/W.This bit is a global enable bit for Device 1 SERR

 

messaging. The MCH does not have an SERR# signal. The MCH communicates the SERR#

 

condition by sending an SERR message to the ICH2.

 

0 = Disable. SERR message is not generated by the MCH for Device 1.

 

1 = Enable. MCH is enabled to generate SERR messages over the hub interface for specific

 

Device 1 error conditions that are individually enabled in the BCTRL register. The error

 

status is reported in the PCISTS1 register.

 

NOTE: This bit only controls SERR messaging for the Device 1. Device 0 has its own SERRE

 

bit to control error reporting for error conditions occurring on Device 0.

 

 

7

Address/Data Stepping (ADSTEP)—RO. Not Implemented; Hardwired to 0.

 

 

6

Parity Error Enable (PERRE1)—RO. Not Implemented; Hardwired to 0.

 

 

 

5

Reserved.

 

 

 

4

Memory Write and Invalidate Enable (MWIE)—RO. Not Implemented; Hardwired to 0.

 

 

3

Special Cycle Enable (SCE)—RO.Not Implemented; Hardwired to 0.

 

 

2

Bus Master Enable (BME1)—R/W.This bit is not functional. It is a R/W bit for compatibility

 

with compliance testing software.

 

 

1

Memory Access Enable (MAE1)—R/W.

 

0 = Disable. All of Device 1’s memory space is disabled.

 

1 = Enable. The Memory and Prefetchable memory address ranges defined in the MBASE1,

 

MLIMIT1, PMBASE1, and PMLIMIT1 registers are enabled.

 

 

0

I/O Access Enable (IOAE1)—R/W.

 

0 = Disable. All of device 1’s I/O space is disabled.

 

1 = Enable. This bit must be set to1 to enable the I/O address range defined in the IOBASE1,

 

and IOLIMIT1 registers.

 

 

 

 

82

Intel® 82845 MCH for SDR Datasheet

Page 82
Image 82
Intel 845 PCICMD1-PCI-PCI Command Register Device, Address Offset 04-05h Default 0000h Access, Access Enable IOAE1-R/W