ZiLOG ZDS-1 Series User Manual page 7

'FFF
1
ADDRESSES
NON-EXISTENT
D E C L A R E D
MEMORY
NON-EXISTENT
I
W R I T E PROTECTED
TO SIMULATE PROMS
I
I
MEMORY
t
- - - -
MEMORY
ALLOCATED TO
(
USER'SSYSTEM
- -
-
-
\
MAPPED TO ZDS-1/40
I
4000
3FFF
1
3000
DEVELOPED
'ROTOTYPE MEMORY
(8192BYTES)
DFFF
ADDRESSES
Development System User's Prototype
Address Space
ZDS-1/40 MEMORY MAPPING
The memory Mapping and Address Translator features
The illustration above shows a typical use of the mapping
allow configuration of the memory used during an emula-
feature and the address translation feature. Undeveloped
tion. Memory is divided into blocks, each containing 1024
PROM's are allocated address space in the development sys-
bytes. Under software control, these blocks of memory may
tem so that software may be debugged prior to fusing the
be assigned to be existent in either the prototype system,
PROM's. This area has been assigned properties of being
or the ZDS-1/40 Development System, to be non-existent
write protected to simulate PROM behavior. If a write is
or write protected.
attempted, it will be inhibited and a break d l occur if
This feature allows the allocation of blocks of develop-
the "Break-on-Write" option has been selected. Addresses
ment system memory to the prototype system thereby em-
4000-FFFF are non-existent and may be declared as such
ulating PROM programs or utilizing memory addresses not
so that any attempted access will also cause a break in pro-
yet developed in the system.
gram execution.
The address translator allows blocks of user memory to
be located around existing software so that resident soft-
ware will remain unaffected.