6 i/o mapped registers, 1 config_address - configuration address register, I/o mapped registers 4.6.1 – Intel D15343-003 User Manual
Page 45: Config_address – configuration address register, Configuration address register
Register Description
D15343-003
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system initialization software (usually BIOS) to properly determine the DDR SDRAM
configurations, operating parameters, and optional system features that are applicable and to
program the GMCH registers accordingly.
4.6
I/O Mapped Registers
The GMCH contains two registers that reside in the CPU I/O Address Space: the Configuration
Address (CONFIG_ADDRESS) Register and the Configuration Data (CONFIG_DATA) Register.
The Configuration Address Register enables/disables the Configuration Space and determines
what portion of Configuration Space is visible through the Configuration Data window.
4.6.1
CONFIG_ADDRESS – Configuration Address Register
CONFIG_ADDRESS is a 32-bit register that can be accessed only as a Dword. A Byte or Word
reference will “pass through” the Configuration Address Register and the Hub interface, onto the
PCI bus as an I/O cycle. The CONFIG_ADDRESS register contains the Bus Number, Device
Number, Function Number, and Register Number for which a subsequent configuration access is
intended.
I/O Address:
Default Value:
Access:
Size:
0CF8h Accessed as a Dword
00000000h
Read/Write
32 bits
Figure 2.
Configuration Address Register
R
1 0
2
7
8
11
15
16
23
24
30
31
10
R
0
0
0
0
0
Reserved
Register Number
Function Number
Device Number
Bus Number
Reserved
Enable
Bit
Default