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8XC196NT USER'S MANUAL
Table 4-15. Memory Map for the System in Figure 4-10
Address
FFFFFF
Unimplemented
FFA000
FF9FFF
Internal OTPROM (code and far constants)
FF2000
FF1FFF
Unimplemented
FF0600
FF05FF
Internal code and data RAM (mapped from page 00H)
FF0400
FF03FF
Unimplemented
FF0100
FF00FF
Reserved
FF0000
0FFFFF
Unimplemented
020000
01FFFF
External far data (implemented by bottom 64-Kbyte external RAM)
010000
00FFFF
External near data (implemented by top 64-Kbyte external RAM)
002000
001FFF
Memory-mapped SFRs
001FE0
001FDF
Peripheral SFRs
001F00
001EFF
External near data (implemented by top 64-Kbyte external RAM)
000600
0005FF
Internal code and data RAM
000400
0003FF
Upper register file (general-purpose register RAM)
000100
0000FF
Lower register file (general-purpose register RAM, stack pointer, and CPU SFRs)
000000
4.6.3
Example 3: A 1-Mbyte 87C196NT System with a 16-bit Bus
Figure 4-11 on page 4-33 illustrates a system designed to operate in 1-Mbyte mode (CCB2.1=0).
Code can execute from any page in the 1-Mbyte address space. EA# is held inactive, so accesses
to FF2000–FF9FFFH are internal. The internal OTPROM is mapped into page 00H (CCB2.2=1),
leaving 32 Kbytes of page 00H available for storing near data. With the OTPROM mapped into
page 00H, the far constants in FF2000–FF9FFFH can be accessed as near constants.
4-32
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