Assignment Of The Memory Addresses - Siemens SIMATIC Box PC 820 Manual

Motherboard
2.10.2

Assignment of the Memory Addresses

There are two kinds of address areas:
S
Memory address area
S
I/O address area.
Different read/write signals (I/O WR, I/O RD, MEMR, MEMW) are used to
reference these areas. The following tables provide you with an overview of the
address areas used. Please refer to the descriptions of the individual functional
groups for more details.
From To
Address Address
0000 0000 0007 FFFF
0008 0000 0009 FBFF
0009 FC00 0009 FFFF
000A 0000 000A FFFF
000B 0000 000B 7FFF
000B 8000 000B FFFF
000C 0000 000D FFFF
000E 0000 000E BFFF
000E C000 000E CFFF
000E D000 000E DFFF
000E E000 000E FFFF
000F 0000 000F FFFF
0010 0000 00EF FFFF
00F0 0000 00FF FFFF
0100 0000 2FFF FFFF
3000 0000 FFEF FFFF
FFF0 0000 FFFD FFFF 1023k-128k
FFFE 0000 FFFF FFFF
2-32
Size Assignment
512k Conventional system memory
127k Conventional system memory
extended
1k Conventional system memory
extended BIOS data
64k Graphics refresh memory
32k SW graphics interface module
32k Graphics refresh memory
148k VGA BIOS expansion and
system resources. The
available area above 000C
7FFF depends on the system
equipment.
48k System BIOS
4k System BIOS
BootMessageLogo
4k System BIOS Plug & Play Area
8k System BIOS Boot Block
64k System BIOS
14M Extended system memory
1M Extended system memory or
Memory hole
768M Extended system memory
4G-768M- PCI expansion; resources are
1023k assigned by the operating
system.
ISA memory, reserved for dual-
port RAM
128k Shadow of System BIOS
(000E 0000 .. 000F FFFF)
Remark
VGA
Vacant
VGA/CGA
VGA
Via BIOS SETUP
Vacant
Box PC 820 / PC FI45 V2, Manual
A5E00051531-03