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Intel® Entry Server Board SE7221BA1-E TPS
Maps and Interrupts
Revision 1.5
21
4. Maps and Interrupts
In this section, Table 5 describes the system memory map, Table 6 shows the I/O map, Table 7
lists the DMA channels, Table 8 defines the PCI configuration space map, and Table 9
describes the interrupts.
4.1 Memory
Resources
4.1.1 Memory
Map
The following table lists the system memory map.
Table 5. System Memory Map
Address Range (decimal)
Address Range (hex)
Size
Description
1024 K - 4194304 K
100000 - FFFFFFFF
4095 MB
Extended memory
960 K - 1024 K
F0000 - FFFFF
64 KB
Runtime BIOS
896 K - 960 K
E0000 - EFFFF
64 KB
Reserved
800 K - 896 K
C8000 - DFFFF
96 KB
Potential available high DOS memory
(open to the PCI Conventional bus).
Dependent on video adapter used.
640 K - 800 K
A0000 - C7FFF
160 KB
Video memory and BIOS
639 K - 640 K
9FC00 - 9FFFF
1 KB
Extended BIOS data (movable by
memory manager software)
512 K - 639 K
80000 - 9FBFF
127 KB
Extended conventional memory
0 K - 512 K
00000 - 7FFFF
512 KB
Conventional memory
4.1.2 Addressable
Memory
The Intel® Entry Server Board SE7221BA1-E utilizes 4 GB of addressable system memory.
Typically the address space that is allocated for PCI Conventional bus add-in cards, PCI
Express* configuration space, BIOS (firmware hub), and chipset overhead resides above the
top of DRAM (total system memory). On a system that has 4 GB of system memory installed, it
is not possible to use all of the installed memory due to system address space being allocated
for other system critical functions. These functions include the following:
•
BIOS/firmware hub (2 MB)
•
Local APIC (19 MB)
•
Digital Media Interface (40 MB)
•
Front side bus interrupts (17 MB)
•
PCI Express* configuration space (256 MB)
•
MCH base address registers, internal graphics ranges, PCI Express* ports (up to 512
MB)
•
Memory-mapped I/O that is dynamically allocated for PCI Conventional and PCI
Express* add-in cards
The amount of installed memory that can be used will vary based on add-in cards and BIOS
settings. Figure 10 shows a schematic of the system memory map. All installed system
memory can be used when there is no overlap of system addresses.