System Memory Map - Epson 486SX User Manual

System Memory Map

02000000h
OO1OOOOOh
000F0000h
000E0000h
000D0000h
000C0000h
000B0000h
000A0000h
00000000h
The system BIOS and VGA BIOS are contained in one 128KB EPROM. The
l
64KB system BIOS and 32KB VGA BIOS ROM are shadowed in RAM after
the system completes power-on diagnostics. The system and VGA BIOS
ROM area in the 000E0000h through 000F0000h range is shadowed at
000E0000h after the system completes power-on diagnostics.
D - 6 Specifications
Extended memory
System BIOS ROM: 64KB*
VGA BIOS: 32KB*
Available
Available
Video memory: 64KB (MDA or CGA)
Video memory: 64KB (EGA or VGA)
Conventional system memory: 640KB
16MB
(Maximum system
memory on SIMMs)
1MB
640KB