Specifications

Chapter 3 Hardware
LittleBoard 800 Reference Manual 19
Memory Map
The following table provides the common PC/AT memory allocations. Memory below 000500h is used by
the BIOS.
I/O Address Map
Table 3-3 shows the I/O address map.
Table 3-2. Memory Map
Base Address Function
00000000h - 0009FFFFh Conventional Memory
000A0000h - 000AFFFFh Graphics Memory
000B0000h - 000B7FFFh Mono Text Memory
000B8000h - 000BFFFFh Color Text Memory
000C0000h - 000CFFFFh Standard Video BIOS
000D0000h - 000DFFFFh Reserved for Extended BIOS
000E0000h - 000EFFFFh Extended System BIOS Area
000F0000h - 000FFFFFh System BIOS Area (Storage and RAM Shadowing)
00100000h
- 04000000h Extended Memory (If on-board VGA is enabled, then the amount of
memory assigned is subtracted from extended memory)
FFF80000h - FFFFFFFFh System Flash
Table 3-3. I/O Address Map
Address (hex) Subsystem
0000-000F Primary DMA Controller
0020-0021 Master Interrupt Controller
0040-0043 Programmable Interrupt Timer (Clock/Timer)
0060-06F Keyboard Controller
0061 NMI, Speaker Controller
0063 NMI Controller
0064 Keyboard Controller
0065 NMI Controller
0067 NMI Controller
0070-007F CMOS RAM, NMI Mask Reg, RT Clock
0080-09F System reserved
0081-0083 DMA Page Registers
0084-0086 System Reserved
0087 DMA page Register
0088 System reserved
0089-008B DMA page Registers
008C-008E System reserved
008F DMA page Register
0090-0091 System reserved
092 Fast A20 Gate and CPU Reset