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General forum - Beta Testers
Bug Report - Beta Testers
Posted: Fri Nov 02, 2007 6:16 pm
Post subject: A little information about FS-A1FM to emulate on blueMSX
It is not so easy to emulate Panasonic's FS-A1FM (FDD with
integrated MSX2 machine)
FS-A1FM includes Panasonic/ASCII 08KB memory Mapper in
But in spite of emulation of Panasonic 08KB mapper, it
Because of modem's emulation with I/O register.
I attach Slot 3-1 / Slot 3-3 for FS-A1FM.
Slot 3-3 is fixed.
But the register on Slot 3-1 is variable.
Here is a little information for FS-A1FM
FSA1FM.ROM (firmware.rom -- 1MB) shows 16 pages repeated twice (0-F == 10-1F)
their content is a mirror of the modem utility that runs
at slot 3-1! In
that slot, there are 16KBytes of Extended ROM at
0000-3FFF, the modem
utility at 4000-5FFF using its own mapper, and ram at
with some I/O ports at 7FC0-7FCF (that's why the files
each different). Switch address is 7FC4, but bits 4-7 are
preserved when paging, so they may have another function
So which pages of slot 3-3's mapper are actually used in
that slot? At
least A8-AF are used, so you'll have to make a longer
dump. By the way,
this slot has ports similar to FS-4600's slot 3-1, though
the mapper is
Ascii 8KB. But I can't assert their exact functionality
until I analyze
the full rom.
FS-A1FM's slot 3-3 Pages 80-FF are all the same as 00-7F
except for this:
80-83, 88-8B: disconnected (all bytes FF).
84-87, 8C-8F: eight mirrors of one only 8KB ram area.
So 00-7F is enough for future emulation.
This is additional data about mapper structure of FS-A1FM:
0000-3FFF: extended bios.
4000-5FFF: secondary mapper on pages 00-0F of Slot 3-3's
address is 7FC4 (bits 0-3).
6000-7FFF: secondary mapper on pages 80-8F of Slot 3-3's
address is 7FC4 (bits 4-7).
Initial value for 7FC4 is undefined. Because of this, all
have the same boot code.
7FC0-7FCF: I/O ports.
Basically an Ascii 8KB megarom. Differences are:
0000-1FFF: extra 8KB bank. Switch address is probably
6400, readable at
2000-3FFF: extra 8KB bank. Switch address is probably
6C00, readable at
Standard switch addresses 6000/6800/7000/7800 are readable
7FF6,7FF7: always read 0.
7FF9: bit 2 (value = 4) activates ports 7FF0-7FF7.
In fact, extra banks are never used. Initial value for all
six banks is
A8 ( = page 2
I think it is different from Panasonic 08KB Mapper for FS-A1WX/WSX/ST/GT.
Here is SLOT31-SLOT33 ROM
P.S. FSM.COM is made by Kichi (Japanese MSX User) to dump
from Modem Mapper Cartridge just like FS-CM1 / FS-A1FM.
This tool may be useful to realize Panasonic Modem Mapper emulation.
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