Is MSX-DOS 2.X ROM a ASCII16 megarom ? Is there any ASCII8 version?

By giangiacomo.zaffini

Champion (267)

giangiacomo.zaffini's picture

05-02-2017, 12:42

I have a MFR+SD+RAM so it is not a question to have a non turboR machine running MSX-DOS 2.X/Nextor,
but as far as I know (I looked at BiFi and BiFi 2 saverom) MSX-DOS 2.X ROM is an ASCII16 megaROM.
Did anybody develop a working ASCII8 version? I think that ASCII8 megaROM are far more easy to find, and I have one doing nothing with it. Is it feasible? Are there tools outthere?
Thank You. :D

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By Grauw

Ascended (9156)

Grauw's picture

05-02-2017, 12:55

By giangiacomo.zaffini

Champion (267)

giangiacomo.zaffini's picture

06-02-2017, 08:54

I will try Nextor then!
Thank You Grauw.
Happy MSX-ing.

By l_oliveira

Hero (530)

l_oliveira's picture

07-02-2017, 00:59

ASCII8 and ASCII16 are just different wirings of the same megarom chip. Some carts even have jumpers you can set to change the mapper type onboard.

By gdx

Prophet (3561)

gdx's picture

07-02-2017, 08:32

How to make a DOS2 for SCC or ASCII8 mapper: https://goo.gl/OwOZwO

By giangiacomo.zaffini

Champion (267)

giangiacomo.zaffini's picture

07-02-2017, 14:56

Thank You for all Your kindly and useful replies.
Yesterday I tested on openMSX with a Panasonic FS A1 WSX with Nextor.ROM ASCII8, some mapped RAM and a floppy image with nextor.sys and COMMAND2.COM and everything was just fine. Played some .OPX tunes with performer OPX v2.0.
This weekend I'll try with a real Panasonic FS A1 FX modified with 512KB mapped RAM and a MegaROM cartridge.
How much I miss my dead FMPAC!! Sad

By Giangiacomo Zaffini 2

Master (211)

Giangiacomo Zaffini 2's picture

04-08-2017, 19:48

My bad, I cannot do it with real hardware! Crying
I used FL8 v 1.32 from GDX in order to flash my MAB 4Mbits (512Kbytes) flash cartridge, but software cannot find hardware (which is Am29F040B-90PC flash memory).
I added some print variables in the software, but it didn't suggested me a fix.

MAB cartridge works to some extent since it was flashed by the manufacturer and ASC8 game flashed can work with it, and my MSX machines are happy of that.

I really do not understand what is going on with all the magic of ASCII ASC8 mapper and all the magic of autoselected mode command sequence of AMD flash memory devices one covering the other, and oh! all the magic of MSX primary and secondary slot selecting!

Why trying every slot when maily two primary slot are used for expansion slot with cartridge slot which are Slot 1 and Slot 2?
Why trying to work with AMD Am29F040B flash only on page 1 (04000h-07FFFh) where Bank 1 should live at power on when any of 4 banks in page 1 and page 2 could do the job?

I need some help. Tongue

By Giangiacomo Zaffini 2

Master (211)

Giangiacomo Zaffini 2's picture

08-08-2017, 21:48

Does MAB 4Mbits ASC8 have a Flash type kind of Flash AMD clone since working in page 1 Bank 1 any bank number doing Autoselect Command Sequence and then reading Manufacturer's Identity Code it gives Continuation Code '7F' instead of AMD '01' ?
Any advice?

By Grauw

Ascended (9156)

Grauw's picture

08-08-2017, 21:55

Something I realised recently, since ASCII8’s bank select registers are in the range 6000H-7FFFH, you can’t flash there. You need to use the 4000H-6FFFH or 8000H-BFFFH range. And Konami mappers can’t be flashed at all… boo.

By Giangiacomo Zaffini 2

Master (211)

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09-08-2017, 23:27

@ Grauw: indeed you can flash in ASC8 Bank 1 (4000h - 5FFFh) because changing bank to a Bank region is a matter of a write operation, ASC8 Bank 1 region and ASC8 Bank 1 changing addresses are disjoint and they live in page 1.

My bad, it took me ages to find out that FL v 1.32 from GDX works after bypass of Manufacturer identity sanity check and Device identity sanity check. Since flash device label says AMD Am29F040B I just made it '07Fh' as AMD Manufacturer ID and I made '07Fh' as Am29F040B Device ID, which is not JEDEC standardised numbering, but I really don't mind.

Ok, I got what I wanted! Cool