Technical Information 1-7
The BIOS programs execute the Power-On Self-Test, initialize processor controllers, and
interact with the display, diskette drives, hard disks, communication devices, and peripher-
als. The system BIOS also contains the Setup program and provides VGA controller sup-
port. The hardware setup default copies the ROM BIOS into RAM (shadowing) for
maximum performance.
System BIOS is located in the upper portion of the Flash ROM and video BIOS in the
lower portion. System BIOS is located between F0000h-FFFFFh and supports shadowing
and shadowed memory. System BIOS is write protected and automatically enabled.
Video BIOS is located between C0000h and C7FFFh. If the internal video is disabled, this
range is mapped to ISA. The system memory map in shown in Table Section 1-3.
Table Section 1-3 System Memory Map
Memory Space
Size
Function
000000-07FFFF
512 KB
Reserved for system base memory
080000-09FFFF
128 KB
Mapped to either system base memory or ISA bus*
0A0000-0BFFFF
128 KB
Mapped to either on-board video memory or ISA video memory
0C0000-0C7FFF
32 KB
Mapped to either on-board video BIOS or ISA video BIOS
0C8000-0EFFFF
160 KB
Mapped to ISA bus
0F0000-0FFFFF
64 KB
Reserved for system BIOS
100000-FDFFFF
14.9 MB
Reserved for Extended and/or Expanded system memory
FE0000-FFFFFF
128 KB
Mapped to ISA bus
1000000- On-Board
14.9 MB
Reserved for Extended and/or Expanded system memory
*Always non-cacheable.
Flash ROM supports the reprogramming of the system and built-in video BIOS. Software
controls this feature via port 94h. Flash ROM programming writes to location 0F0000h-
0FFFFFh. This range allows access to 64 KB of the 128 KB ROM. To write to the rest of
the ROM, bit 3 of port 94h must be set. Again, writing to 0F0000h-0FFFFFh allows the
rest of the ROM to be programmed. (Setting bit 3 on port 94h maps the 0F0000h to
0E0000h range.)
Power Management
Each computer system incorporates power management features that lowers power con-
sumption when there is no activity detected from the keyboard, mouse, diskette drive, CD-
ROM reader, or hard disk drive after a pre-defined period of time. As soon as activity is
detected the system resumes where it left off.
