Zilog Z80195 User Manual
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Z80185/195 D
EVELOPMENT
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UM951800100
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ILOG
Debug Monitor Memory Map
The Debug Monitor sets the ROM/RAM boundary to hex 02000, so in effect it takes up the first 8K bytes
of the Z80185 address space. Since there is 128K bytes of RAM on the board, the Debug Monitor
sets the top of RAM to 21FFF. The latter 72K bytes of this RAM can only be accessed by using the
Z80185’s Memory Management Unit (MMU).
The Debug Monitor also uses the first 256 bytes of RAM, addresses 02000-020FF, for its variables,
stacks, and tables. When you apply power to the board or press RESET, the user Stack Pointer (SP)
is set to 00000, so that the first stack locations used will be 0FFFE and 0FFFF, and the Monitor sets
its user Program Counter value (PC) to 02100. 02100 is the suggested starting address for programs
downloaded and run under the Debug Monitor. Higher starting addresses are acceptable.
No Memory
User RAM
(Accessible without MMU)
Monitor RAM
Reserved (ROM)
Debug Monitor (ROM)
Contents
Memory Address
00000
. . .
01A??
. . .
01FFF
02000
. . .
020FF
02100 (PC after RESET)
. . .
. . .
0FFFF (STACK after RESET)
10000
. . .
. . .
21FFF
22000
. . .
FFFFF
User RAM
(Accessible via MMU)
Figure 3-1. Debug Program Memory Map