ST90158 - REGISTER AND MEMORY MAP
3.3 MEMORY MAP
Figure 18. Memory Map
3FFFFFh
Upper Memory
(usually RAM mapped
in Segment 23h)
External
Memory
230000h
22FFFFh
SEGMENTS 21h and 22h
128 Kbytes
Reserved
210000h
20FFFFh
20FFFFh
20FD00h
Internal
RAM
768 bytes
PAGE 83 - 16 Kbytes
20C000h
20BFFFh
PAGE 82 - 16 Kbytes
PAGE 81 - 16 Kbytes
PAGE 80 - 16 Kbytes
SEGMENT 20h
64 Kbytes
208000h
207FFFh
1 Kbytes
20FC00h
20FA00h
20F800h
204000h
203FFFh
1.5 Kbytes
200000h
1FFFFFh
2 Kbytes
Lower Memory
(usually ROM/EPROM mapped
in Segment 1)
External
Memory
010000h
00FFFFh
00FFFFh
00BFFFh
007FFFh
64 Kbytes
PAGE 3 - 16 Kbytes
00C000h
00BFFFh
48 Kbytes
32 Kbytes
PAGE 2 - 16 Kbytes
PAGE 1 - 16 Kbytes
PAGE 0 - 16 Kbytes
SEGMENT 0
64 Kbytes
Internal ROM/EPROM
(external ROM on
ROMless devices)
008000h
007FFFh
00FFFFh
Internal
ROM
004000h
003FFFh
24 Kbytes
000000h
000000h
Note: The total amount of directly addressable external memory is 64 Kbytes.
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ETC [ ETC ]
