NMS8245 2+ upgrade

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Van Philip

Champion (371)

afbeelding van Philip

22-08-2018, 13:17

msd wrote:

Another reason the boot logo is lost, is that it is in the kanji Rom. Which doesn't fit into the 64k Rom of the 8245.
I doubt that. The kanji is in a different rom iirc, when msx2 are modified to 2+ this is not included anyway, but perhaps an already modified ROM was just for this. I have a nms8245 modified to 2+ which has a boot logo.. (it ofcourse has the f4 register).

Best is to add this register.. keeping the 2.1 rom is just not as good as it can be imho.

Well, my 8245 also has the boot logo, without F4 register. I just pathed the bios to not look at it.

All the rom's used for 2+ conversion I found in the internet have the kanji rom, most likely your 8245 also has it.
Just try _kanji (without msxdos2 rom).

Van msd

Paragon (1372)

afbeelding van msd

22-08-2018, 14:40

I Yes kanji basic , you are Right . Confused With jis for a moment

Van karloch

Prophet (2058)

afbeelding van karloch

26-08-2018, 11:24

Allow me to resurrect the thread just a bit: imagine you have the Spanish 8245 model with the Ñ key and the support in the BASIC ROM. As there are not even European MSX 2+, there is no way to keep the Ñ support after the upgrade, right?

Van NYYRIKKI

Enlighted (5320)

afbeelding van NYYRIKKI

26-08-2018, 13:14

Ok, let me say few words about this issue as well....

The F4-port is not that important... MSX2 does not have this either and therefore it always displays boot logo no matter if the machine is booted by software or hardware. If this is fine for you also in MSX2+ then there is no problem... Personally I replaced F4-port with RETURN-key. -> If return is not pressed the logo is displayed and if return is pressed, then the logo is skipped. This kind of works since many times when you execute some command to perform soft reset, you apply the command with RETURN-key anyway...

After adding all V5558 related stuff to SUB-ROM there was indeed no space to fit in logo anymore... Because MSX2+ was made only in Japan, they moved the logo to Kanji BASIC ROM. How ever in European machines the Kanji BASIC ROM is pretty useless... Especially since machines here don't have the actual Kanji Font ROM. In case you have some other rom with some free space it is not very hard to move the logo to that space, but in case of 8245 that is not natively possible because there is only 64KB of ROM.

The options are therefore to add additional ROM that requires some extra soldering. (See page 1) OR you can use ROM that I've made for this kind of upgrades. (Send me a mail) In later case the issue is solved by making much smaller replacement for the logo routine and cramming it back to SUB-ROM where it was on MSX2... Naturally some details have needed to go like M and S, smooth edges and the fade routine is more simple, but this can be used as drop in replacement without need for adding extra ROM... I know there is at least one 8245 upgrade out there that has been done like this... You can see the boot here: https://www.youtube.com/watch?v=agTKARNLQk8

In case you want to make ie. Spanish MSX2+ changing keyboard driver is one thing, but there are lot of more things to consider as well... Keyboard driver is quite easy to copy/paste from old MSX2 ROM. (Usually #0DA5-#10C2 & #1B94-#1BAB in MAIN ROM is enough) and AFAIK fonts are always in #1BBF, but you can check that with ?PEEK(4)*256+PEEK(5)

One very important question is also if you want to make the computer boot to 50Hz (Spanish standard) or 60Hz (As MSX2+ computers do in Japan)... I "solved" this by adding this selection to "H"-key during boot, but even in this case you still need to figure out what is your default and on which mode you want your boot logo displayed.

After that you may want to consider what you want to put to #2B & #2D in MAIN ROM... SET/GET DATE & TIME commands are different in Japan and Spain and this may be a bit harder to fix (These commands are implemented in SUB-ROM) There are also lots of other minor things to consider like functionality of PRINT USING-command, should keyboard scan interval be changed to match 50Hz scenario etc.

Van karloch

Prophet (2058)

afbeelding van karloch

27-08-2018, 01:37

Quite a clear explanation! Thank you NYYRIKKI. Excuse my ignorance, but, what is the F4 register and why is it used by the MSX 2+?

Van NYYRIKKI

Enlighted (5320)

afbeelding van NYYRIKKI

27-08-2018, 07:51

karloch wrote:

Quite a clear explanation! Thank you NYYRIKKI. Excuse my ignorance, but, what is the F4 register and why is it used by the MSX 2+?

F4 register is 1bit of memory that is used to track if the computer is booted by hardware (ie. power on) or software (ie DEFUSR=0:A=USR(0)) ... in later case the display of boot logo is skipped. The name comes from the fact that it is connected to bit 7 of I/O port #F4. There exists two versions that return either same value that was written or inverted value and therefore it should not ever be used directly but using MAIN BIOS calls #17A (read) and #17D (write). The MSX2+ BIOS inserts CPL-command on read if hardware requires it.

Van karloch

Prophet (2058)

afbeelding van karloch

27-08-2018, 21:32

Just tried the code on my MSX (turboR) and indeed, it rebooted without showing the logo again. Really usefull for speeding up the process. Something more I know about, thank you!

Van mohai

Paladin (826)

afbeelding van mohai

28-08-2018, 17:49

karloch wrote:

Allow me to resurrect the thread just a bit: imagine you have the Spanish 8245 model with the Ñ key and the support in the BASIC ROM. As there are not even European MSX 2+, there is no way to keep the Ñ support after the upgrade, right?

There are already patched ROMs for Spanish keyboard. Some of them with F4 support, some others not. I upgraded a couple of 8280. One with Spanish keyboard and one with ingernational keyboard.
Those ROMs should be somwhere in the Net. E-mail me if you don't find them.

Van luppie

Paladin (854)

afbeelding van luppie

30-08-2018, 13:10

Quote:

For the kanji rom I've used a 27c512 but a 27c256 should also work.
It should have this layout (for a 27c256 just skip the 2nd half):
0000-3fff kanji rom 2nd 16k block
4000-7fff kanji rom 1st 16k block
8000-bfff kanji rom 2nd 16k block
c000-ffff kanji rom 1st 16k block

I'm wondering, since the kanji rom is written double to a 27c512, would it be possible to have a different rom next to the kanji rom. For example the FM-Pak rom, so it would be possible to build in and use a YM2413 for msx-music.
What would be the best rom layout and/or what extra connections are needed to acces this rom ?

Van Wolverine_nl

Paladin (1022)

afbeelding van Wolverine_nl

01-09-2018, 19:09

luppie wrote:
Quote:

For the kanji rom I've used a 27c512 but a 27c256 should also work.
It should have this layout (for a 27c256 just skip the 2nd half):
0000-3fff kanji rom 2nd 16k block
4000-7fff kanji rom 1st 16k block
8000-bfff kanji rom 2nd 16k block
c000-ffff kanji rom 1st 16k block

I'm wondering, since the kanji rom is written double to a 27c512, would it be possible to have a different rom next to the kanji rom. For example the FM-Pak rom, so it would be possible to build in and use a YM2413 for msx-music.
What would be the best rom layout and/or what extra connections are needed to acces this rom ?

This would be intersting to know actually Smile

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