The OUT (#99) discussion (again?)

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Por Wlcracks

Hero (515)

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31-01-2019, 18:37

is it #99 #98?

Por Grauw

Ascended (10699)

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31-01-2019, 19:17

No, V9990 uses ports 60H-6FH and is not compatible with TMS9918.

However Franky and PlaySoniq use the Sega VDP which is compatible with TMS9918, and is also located at port 88H. They don’t modify the addresses in the BIOS though, they aren’t intended as an upgrade cartridge for existing software. More useful for dedicated software or dual screen type of applications I reckon. No superimposing function unfortunately.

Wlcracks wrote:

Like i mentioned in the first sentence, its for MSX1.

Ah, ok, I missed that part hehe. In that case I think there is less reason to support alternate ports. Owners of an MA-20 or clone can just unplug it. Though it is a bit of a hassle to unplug I guess, so at most it’s a matter of being friendly.

Wlcracks wrote:

When using a ROM you cannot pre-render the port in code (Mmm thinking now: maybe only the fast parts in RAM).

Indeed you can, but this is what I meant by “ease of use” Smile.

Then again, one may wonder when you actually need this speed, since bulk data output already uses the c register, and also for sprite writes using c is convenient because you can out any register rather than just a (I do this in my RPG in development). So only register writes would really be optimised or simplified, and those are a relatively rare occurrence.

Wlcracks wrote:

The reactions amaze me, using 99 98 is not done but when using psg direct port nobody cares, while this could actually blow up an MSX1.

I guess it may be because there’s no actual hardware which replaces the PSG by changing the BIOS.

But there’s definitely people who are very adamant about using the BIOS for everything Smile.

Por zett

Hero (608)

imagem de zett

31-01-2019, 19:59

Pencioner wrote:
zett wrote:

dont use the vdp9938 cardrige. its not real. with it you just have a msx1 with 2 vdps. ppl dont go that way. its evil

what about v9990 cartridge? is it more evil or less evil? LOL!

less, even not evil ad all

Por NYYRIKKI

Enlighted (6016)

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01-02-2019, 07:24

Wlcracks wrote:

In that case I think there is less reason to support alternate ports. Owners of an MA-20 or clone can just unplug it.

Actually, if you hard code everything and do not rely to BIOS on VDP related things, there is no even reason to unplug MA-20 clone... I say clone, because on real MA-20 the updated BIOS was delivered on separate cartridge I believe, so it would be enough to eject the software cartridge (In case your software is on cartridge I think this is something user would do anyway... Unless she has slot expander and...)

Por gdx

Enlighted (6071)

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01-02-2019, 08:42

gdx wrote:

MSX2 upgrades also cause incompatbilites with software that uses 64KB on MSX with the slot 0 expanded and with keyboard layouts.

In fact, it cause incompatibilities with software that uses 64KB on MSXs that have the slot 0 expanded and the RAM is in one fo these slots. Fortunately, there are probably not MSX1 like that.
I only saw the Korean MSX2s in this case. It's a shame because the Bios do not like this configuration.

The MA-20 must also be unplugged for MSX1 programs that consider only the bit 7 of address 0FCC1h.

Por Wlcracks

Hero (515)

imagem de Wlcracks

01-02-2019, 17:41

NYYRIKKI wrote:
Wlcracks wrote:

In that case I think there is less reason to support alternate ports. Owners of an MA-20 or clone can just unplug it.

Actually, if you hard code everything and do not rely to BIOS on VDP related things, there is no even reason to unplug MA-20 clone... I say clone, because on real MA-20 the updated BIOS was delivered on separate cartridge I believe, so it would be enough to eject the software cartridge (In case your software is on cartridge I think this is something user would do anyway... Unless she has slot expander and...)

Lol did i write that hehe oO I cannot even spell alten.... what he said

Por Grauw

Ascended (10699)

imagem de Grauw

02-02-2019, 00:09

Riiight so if you e.g. use the BIOS to select the screen mode, and then don’t use the I/O ports indicated by 6H and 7H, that’s when the real problems start. Hadn’t even considered that.

I do think using the BIOS to select screen mode rather than fiddling all the bits yourself is rather nice.

Por gdx

Enlighted (6071)

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03-02-2019, 09:35

Quote:

In fact, it cause incompatibilities with software that uses 64KB on MSXs that have the slot 0 expanded and the RAM is in one fo these slots. Fortunately, there are probably not MSX1 like that.
I only saw the Korean MSX2s in this case.

It's wrong. Following MSX1 have the RAM is in slot 0-2.
Sakhr AX-150, AX-200, AX-330,
Bawareth Perfect MSX1
Daewoo zemmix CPC-51
And probably more...

Por Wlcracks

Hero (515)

imagem de Wlcracks

03-02-2019, 12:52

do they have some kind of an engine? The subslots would have given extra production costs.

Por NYYRIKKI

Enlighted (6016)

imagem de NYYRIKKI

04-02-2019, 05:13

Wlcracks wrote:

do they have some kind of an engine? The subslots would have given extra production costs.

Yes... I would say DW64MX1 is the "source of evil" in this case.

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