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4.
SYSTEM
DESCRIPTION
4-1.
Memory map
a) At power
on
$0000
$1000
$1200
$0000
$0800
$EOoo
$FOoo
MONITOR
(ROM)
MONITOR WORK
SYSTEM
and
TEXT
AREA
(DRAM)
V·RAM<CHARACTER>
(SRAMI
V·RAM<COLORDATA>
(SRAMI
KEY
and
TIMER
PORT
FLOPPY CONTROLLER
Enable
$0000
$1000
$0000
SYSTEM
(DRAM)
and
TEXT
AREA
SYSTEM
and
TEXT
AREA
(DRAM)
Disable
• Shown above
is
the memory map at the time
of
power
on.
VRAM
contents from$DOOO to $DFFF differ from
the
MZ·80K.
• The monitor (ROM) has the same entry point
as
that
of
the MZ·80K.
b) Bootstrap (loading
of
system program)
$0000 $0000
MONITOR
Ir--
(ROfv\)
1'-
SYSTEM
$1000
LOAD
SYSTEM
$7EOD
Boot PROGRAM
~
'11
$0000
$0000
V·RAM
V·RAM
$EOoo
KEY and
TIMER
PORT
SYSTEM
Eneble
Disable
• With the input
of
the LOAD command
of
the monitor,
the
BASIC
loading program
is
transferred
to
the system
area composed
of
the
RAM
and starts
to
bootstrap.
(Only the cassette tape
is
subject
to
bootstrapping in
this case).
4
• Boot command: L
• With the entry
of
the boot command
L,
only the tape
loading program
is
transferred
to
the system area and the
system program
is
loaded
to
the system area designated
in the DRAM.
NOTE: The boot program shown in the figure
is
the
program loaded from the tape and
is
not the
program from the monitor
(ROM).
c) System initiation
$0000
$1000
MONITOR
(ROM)
.$0000
,-------,
V·RAM
V·RAM
$Eooo I--KE-Y-ond-TI-M-ER-P-OR-T-l
:$Fooo
1--------1
Disable
$0000
,-----,
SYSTEM
$1000 ----------------------
$0000
---------------------------
Enable
• The above memory map is valid upon completion
of
system program loading.
• The system program
is
programmed
to
switch the
memory depending upon what
is
accessed,
VRAM,
keyboard, or timer.
d) At
the
time
of
manual reset
$0000
$1000
MONITOR
(ROM)
$0000 I SYSTEM
$1000
~-----~
SYSTEM
$0000
$0000
,-------,
V·RAM
V-RAM
$EOoo
KEY
and
TIMER
PORT
SYSTEM
$FOoo
Enable
Disable