2. sdì (system loading & cp/m), Mzs.'too – Sharp MZ-3500 User Manual
Page 10
Attention! The text in this document has been recognized automatically. To view the original document, you can use the "Original mode".
ROM-IPL
1.
An 8KB ROM (2764 or mask ROM equivalent) is used
for the ROM-IPL.
2.
When the system reset signal turns from low to high
state after power on, the main CPU starts to operate At
this stage, the ROM-IPL is addressed.
3. The CPU starts from address OOOOIROM address 10000)
4.
The main CPU sets the sub-CPU reset signal from low to
high state as it goes out of its initial state via the memory
mapper and the sub-CPU starts to operate. At this point,
the ROM-IPL is addressed by the sub-CPU.
5.
Address 0000 of the sub-CPU is ROM address (0000)
The
memory
area
above
ROM
address
(1000)
cannot
be used by the sub-CPU because the mam CPU initial
program has been loaded there.
2-2. SDÌ (SYSTEM LOADING & CP/M)
SDÌ
determines
which
operating
system
is
in
use.
The
system is loaded in the CP/M (Control Program for Micro
processors) mode.
MZS.'tOO
Mam CPU logical address (during IPL operation)
Logical address of the sub-CPU
ROM physical address
М Ы = 0 ( L )
W S 0 = l ( H j
F F F F
i
P 8 0 0
F 7 F F
*
i. Л 0 n
\
' \
\\
\ \
\ \
\ \
\ \
\ \
\ \
\ \
\ \
V \
\ \
\ \
\ \
\ \
\ \
\'
----- T
R A M
s n
R A M
S C
R A M
S B
R A M
S A
5 F F F
5 8 0 0
5 7 F F
5 0 0 0
4 F F F
4 8 0 0
4 7 F F