JG82855GMESL7VN Datasheet, PDF (123/213 Pages) Intel Corporation – Intel® 855GM/855GME Chipset Graphics and Memory Controller Hub (GMCH)

Intel® 855GM/GME GMCH System Address Map
R
5
5.1
Intel^® 855GM/GME GMCH System
Address Map
A system based on the GMCH supports 4 GB of addressable system memory space and
64 kB+3B of addressable I/O space. The I/O and system memory spaces are divided by system
configuration software into regions. The system memory ranges are useful either as system
memory or as specialized system memory, while the I/O regions are used solely to control the
operation of devices in the system.
When the GMCH receives a Write request whose address targets an invalid space, the data is
ignored. For Reads, the GMCH responds by returning all zeros on the requesting interface.
System Memory Address Ranges
The GMCH provides a maximum system memory of 2-GB. The GMCH does not remap APIC
memory space and does not limit DDR SDRAM space in hardware. It is the BIOS or system
designer’s responsibility to limit system memory population so that adequate PCI High
BIOS and APIC memory space can be allocated. Figure 6 and Figure 7 depict the system
memory address map in a simplified form and provide details on mapping specific system
memory regions as defined and supported by the GMCH.
Datasheet
123