Technical Information 1-7
Table 1-3 System Memory Map
Memory Space
Size
Function
000C0000-000C7FFF
32 KB
Video BIOS (Shadowed in DRAM)
000A0000-000BFFFF
128 KB
Video Buffer (SMM space Non-Cacheable)
00080000-0009FFFF
128 KB
Optional memory space gap (DOS Apps)
00000000-0007FFFF
512 KB
DOS applications (No read/write protect) (Always
cacheable)
Power Management
Each system incorporates power management features that lower power consumption 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.
With Power Management enabled (shipped enabled), the system automatically activates the
power-saving features and enters a suspend mode whenever inactivity is sensed.
I/O Addressing
The processor communicates with I/O devices by I/O mapping. The hexadecimal (hex)
addresses of I/O devices are listed in Table Section 1-4.
Table Section 1-4 I/O Address Map
Address (Hex)
I/O Device Name
0000-000F
DMA controller 1 (channel 0-3)
0020-0021
Interrupt controller 1
0040-0043
Timer 1
0048-004B
Timer 2
0060
Keyboard controller data byte
0061
NMI status and speaker control
0064
Keyboard controller cmd/status byte
0070-007F
Real-time clock, NMI mask
0080-008F
DMA page registers
00A0-00A1
Interrupt controller 2
00C0-00DE
DMA controller 2
00E0-00EF
Reserved
