4.SYSTEM DESCRIPTION
4-1. Memory map a) At power on
$0000
MONITOR (ROM)
$1000 MONITOR WORK $1200
SYSTEM
and
TEXT AREA
(DRAM)
$0000
V·RAM<CHARACTER>
(SRAMI
$0800
V·RAM<COLORDATA>
$0000
$1000
$0000
SYSTEM (DRAM)
and
TEXT AREA
•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$0000 ,
MONITOR
(ROM)SYSTEM
$EOoo
(SRAMI
$1000$1000
SYSTEM
KEY and TIMER PORT
$FOoo
FLOPPY CONTROLLER
Enable
and
TEXT AREA
(DRAM)
Disable
.$0000 ,
V·RAM
V·RAM
•Shown above is the memory map at the time of power on. VRAM contents from$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)
$Eooo
:$Fooo 1 | 1 |
DisableEnable
$0000
$1000
$7EOD
$0000
MONITOR | ||||
(ROfv\) | 1' |
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SYSTEM |
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Boot PROGRAM | ~ |
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$0000
LOAD
$0000
SYSTEM
•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
$EOoo
V·RAM |
V·RAM |
KEY and TIMER PORT
SYSTEM
$0000
$1000
$0000
MONITOR (ROM)
SYSTEM
$0000 I SYSTEM
$1000 | ~ |
$0000 ,
EnebleDisable
•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).
$EOoo
$FOoo
V·RAM
KEY and TIMER PORT
SYSTEM
EnableDisable
4