FW82801DB S L66K Intel, FW82801DB S L66K Datasheet - Page 243

• Manufacturer Part Number: FW82801DB S L66K
• Manufacturer: Intel

Specifications of FW82801DB S L66K

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Register and Memory Mapping
Intel
®
82801DB ICH4 Datasheet
The ICH4 contains registers that are located in the processor’s I/O space and memory space and
sets of PCI configuration registers that are located in PCI configuration space. This chapter
describes the ICH4 I/O and memory maps at the register-set level. Register access is also
described. Register-level address maps and Individual register bit descriptions are provided in the
following chapters. The following notations and definitions are used in the register/instruction
description chapters.
RO
WO
R/W
R/WC
R/WO
Default
Bold
Read Only. In some cases, If a register is read only, writes to this register
location have no effect. However, in other cases, two separate registers
are located at the same location where a read accesses one of the registers
and a write accesses the other register. See the I/O and memory map
tables for details.
Write Only. In some cases, If a register is write only, reads to this register
location have no effect. However, in other cases, two separate registers
are located at the same location where a read accesses one of the registers
and a write accesses the other register. See the I/O and memory map
tables for details.
Read/Write. A register with this attribute can be read and written.
Read/Write Clear. A register bit with this attribute can be read and
written. However, a write of 1 clears (sets to 0) the corresponding bit and
a write of 0 has no effect.
Read/Write-Once. A register bit with this attribute can be written only
once after power up. After the first write, the bit becomes read only.
When ICH4 is reset, it sets its registers to predetermined default states.
The default state represents the minimum functionality feature set
required to successfully bring up the system. Hence, it does not represent
the optimal system configuration. It is the responsibility of the system
initialization software to determine configuration, operating parameters,
and optional system features that are applicable, and to program the
ICH4 registers accordingly.
Register bits that are highlighted in bold text indicate that the bit is
implemented in the ICH4. Register bits that are not implemented or are
hardwired will remain in plain text.
Register and Memory Mapping
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