Where is the bootscreen? That is the question! :D

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By Alexandre_Taito

Champion (325)

Аватар пользователя Alexandre_Taito

17-01-2007, 13:25

A little history here:
All MSX2+ are japanese. Period. So all of them has more or less the same config and ROM structure.

Said that, here we go: In Brazil, all MSX2+ conversion kits were made by(or copied from) Ademir Carchano. We don't speak japanese, so we don't need KANJI ROM. So...All the brazilian converted MSX2+ have the same boot screen - a copy of the Turbo-R boot screen. It was done because the 2+ boot screen is coded on the KANJI ROM, dunno why, maybe there were not enough space on the SUB ROM to store it, as in the 2.0. Since brazilian kits has no KANJI ROM, Ademir inserted the turbo-r boot code into the SUB-ROM of his kits.

Needless to say, it is ugly. Seems the computer is not fast enough to run the screen code as fast as Turbo-R, so all the brazilian converted 2+ has this same ugly screen. Bad.

What do I want: I need to understand HOW the boot screens work. The 2+ has the boot screen code into the Kanji ROM, and I wasn't able to isolate the code. I want to isolate the original code of the 2+ boot screen, and insert that on the ROMs used by the brazilian 2+ kits. Before asking, I searched all the net (and some MRC) for this info and wasn't able to find. Some good soul could enlight me on this subject?

As soon as I get this, I'll write a page describing the entire mod. So any 2.0 converted to 2+ (yes, I'm talking also to you, philips owners) will have a most original 2+ with the proper boot screen.

The ROMs with the turbo-r boot code and FM music (F4 register and RTC disabled) are HERE: http://www.tabajara-labs.com.br/msx/conversao2plus/rom2plus.zip
As far as I know they can be used on any converted 2+. If your MSX board doesn't provide the address line A14 on the socket, you have to pull pin 27 of the SUB-ROM (27C256) and connect to line A14 of any of the slots. To test if your SUB-ROM socket has line A14 connected, measure continuity between pin 27 of the SUB-ROM socket and pin 25 of any of the slots (is the 13rd from left to right, on the botton). FYI the turbo-r code is from 7900 to 7FFF in this sub-rom.

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By SLotman

Paragon (1242)

Аватар пользователя SLotman

17-01-2007, 13:41

Are you sure about this? How could Ademir store turbo-R's boot on MSX2+ kits if turbo-Rs where released much later than the kits itself?

Now, if you want to know how the boot works on 2+ kits, your best bet is asking Ademir himself, through MSXBR-L or his email on his website...

By ro

Scribe (4902)

Аватар пользователя ro

17-01-2007, 13:53

I'd rather have a BOOTless MSX (aka: FAST resetting)
(ah, savestates on emu rule Smile )

By Alexandre_Taito

Champion (325)

Аватар пользователя Alexandre_Taito

17-01-2007, 18:39

Slotman: Good question, have you seen the expert3 boot? What is that so?
I want to know about the 2.0 boot and not about the 2+. Thanks anyway

Ro: Easy, just change one instruction on your main rom. Or disable the kanji rom in 2+

By Manuel

Ascended (19273)

Аватар пользователя Manuel

17-01-2007, 19:43

AFAIK, European MSX2+ conversions have that kanji-basic ROM to provide the boot screen.

By zeilemaker54

Champion (345)

Аватар пользователя zeilemaker54

18-01-2007, 09:17

Bootscreen code on a MSX2+ is indeed in the KANJI BASIC ROM. The routine is located at 07A00H-07FFFH. The bootcode of MSX2+ (in the subrom ) just calls this routine with a interslot call. Note that the code assumes that the KANJI BASIC ROM is in the same slot as the subrom. There is simply not enough space for the bootcode. To make the MSX2+ design cost effective, they simply search for space and found some in the KANJI BASIC ROM.
The MSX-Turbo-R has the bootscreen code in a seperate ROM which is generally called the option rom. The bootscreen code does not fit in the KANJI BASIC ROM of the Turbo-R and therefore a seperate ROM has to be used. There is nothing more in this ROM.

I would not mind if the bootscreen is missing, because it makes the startup a bit faster.

By Alexandre_Taito

Champion (325)

Аватар пользователя Alexandre_Taito

18-01-2007, 12:41

Zeilemaker54, I tried to cut and paste the code from 7A00 to 7FFF to the boot area of the brazilian 2+ in 7900 and filling the rest with FFs. Not worked. Seems I'll have to disassemble the code Sad Thanks anyway! Smile

By ro

Scribe (4902)

Аватар пользователя ro

18-01-2007, 14:03

Zeilemaker told me he already had the disassembled sources and provided them with comment Wink (hint: upload?)

By zeilemaker54

Champion (345)

Аватар пользователя zeilemaker54

18-01-2007, 14:43

As ro stated, I already have a disassembled source file of the MSX2+ subrom. It almost ready for uploading to my msxsyssrc sourceforge project (sourceforge.net/projects/msxsyssrc). Already in the project is the Turbo-R version of the systemrom's.

I will take a look at your rom's to see if something is different from a japanese version...

By zeilemaker54

Champion (345)

Аватар пользователя zeilemaker54

18-01-2007, 15:12

After a quick look:
I see that your version of the subrom starts the logo routine at 07900H, so put a JP 07A00H at 07900H and it should work ok

I assume that looking at the rom file you include, your hardware has the SUBROM (page 0) and FMPAC-ROM (page 1) in the same slot ? And you put the 'logo' code at 07A00H ?
And from what ROM-file you are taking the 'logo' code ? You should use the SUBROM of a Panasonic_FS-A1FX, Panasonic_FS-A1WSX, Panasonic_FS-A1WX, Sanyo_PHC-35J, Sanyo_PHC-70FD or
Sanyo_PHC-70FD2...

By Alexandre_Taito

Champion (325)

Аватар пользователя Alexandre_Taito

18-01-2007, 20:00

Thanks for the help, Zeilemaker! I'm using the MSX-KANJI.rom that cames with the BlueMSX. "My" rom is the rom from the Expert3 board made by Ademir Carchano (www.msxprojetos.com.br). It is a 64K ROM with everything. Your assumptions are right. Does the 2+ boot screen code use direct adressing/jumping? Can't I relocate the code to 07900h and it would work (no, I tried)?

I'm doing the tests right now and I'll be right back with the answers. Thanks!

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