Which MSX1 has which VDP exactly?

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بواسطة amigaman07

Rookie (20)

صورة amigaman07

25-07-2014, 04:36

My Yamaha CX5M has "TMS9929ANL"

On PCB (Mainboard) Under the CHIP it states: TMS9928A also (TMS9918A)

Darren (amigaman07)

بواسطة l_oliveira

Hero (534)

صورة l_oliveira

25-07-2014, 04:52

amigaman07 wrote:

My Yamaha CX5M has "TMS9929ANL"
On PCB (Mainboard) Under the CHIP it states: TMS9928A also (TMS9918A)

That's because on NTSC countries they can use TMS9918A and a single transistor amplifier for composite video output (cost reduction) so the board is marked as compatible with both. If the computer is equipped with TMS9928 (NTSC version capable of output signals that can be converted to RGB signals) or TMS9929 it requires an separated video encoder board which is fairly expensive and complex.

So it's usual that cheaper models use TMS9918 or TMS9118 on their NTSC version.

Like I said before, there is no PAL version of the VDP which is capable of outputting composite video.

بواسطة ARTRAG

Enlighted (6845)

صورة ARTRAG

25-07-2014, 08:50

l_oliveira could you test a rom on a NTSC TMS ? I did tests for uridium mainly on PAL msx1 and msx2 and upper

بواسطة l_oliveira

Hero (534)

صورة l_oliveira

25-07-2014, 14:08

I did, yesterday, when it was suggested that Uridium could be used as a VDP benchmarking and that it was unlikely it would work on NTSC TI VDPs:

TMS9128:

TMS9928:

It's very curious that only sprites did glitch ...

Don't feel bad as for example, this is what happens when you try Guru Logic on a NTSC MSX1:

If I put the original PAL VDP back on the machine it looks like this:

For that kind of thing, Open MSX is starting to work towards emulating chip behavior down to access timing. Aiming to be a useful reference for development.

Edit:
Oh and of course, if I put the PAL VDP back:

بواسطة amigaman07

Rookie (20)

صورة amigaman07

25-07-2014, 16:05

Hi l_oliveira, what do you mean by "there is no PAL version of the VDP which is capable of outputting composite video"???

My Toshiba HX-10 MSX is a PAL UK Computer, and the Composite Out works Fine on all TV sets???

Darren (amigaman07)

بواسطة l_oliveira

Hero (534)

صورة l_oliveira

25-07-2014, 16:19

amigaman07 wrote:

Hi l_oliveira, what do you mean by "there is no PAL version of the VDP which is capable of outputting composite video"???

My Toshiba HX-10 MSX is a PAL UK Computer, and the Composite Out works Fine on all TV sets???

I meant that for it to give out composite video it needed a very complex circuit board with many chips.

NTSC version of same MSX just need a very simple circuit because VDP has all NTSC video hardware inside (Texas Instruments is an American company and their TV standard is NTSC... That kind of make sense, no ?) Cool

بواسطة amigaman07

Rookie (20)

صورة amigaman07

25-07-2014, 16:38

Yes, that makes sense, thank you.

May I also ask you, I have another Yamaha CX5M MSX Computer, and when i switch On, she Powers up (LED on Power Supply and LED on Computer) but only Displays Black Screen.

Do you have any idea what is Wrong with it?

What Chip or Part may have gone Faulty?

As it is in Near Mint condition, almost like New, and would be a shame if I could not have it Fixed.

Darren (amigaman07)

بواسطة Grauw

Ascended (10604)

صورة Grauw

25-07-2014, 16:54

Could be a lot of things. There are definitely people around here who can probably help you debug it. Best start another thread about it though to prevent this one from going off-topic Wink.

بواسطة sd_snatcher

Prophet (3510)

صورة sd_snatcher

25-07-2014, 17:07

Curiously enough, the T6950 has a complete TV-Encoder inside. It changes the format of the output signal between NTSC & PAL according to the selection pin. It's no only an 50Hz/60Hz selector, but really the complete encoding.

This explains why this VDP is seen on both PAL and NTSC machines even when it has only a composite video output like the TMS9118.

I guess that the T7379A composite video output behaves similarly.

بواسطة Fabf

Champion (264)

صورة Fabf

25-07-2014, 17:15

Quote:

That's because on NTSC countries they can use TMS9918A and a single transistor amplifier for composite video output (cost reduction) so the board is marked as compatible with both. If the computer is equipped with TMS9928 (NTSC version capable of output signals that can be converted to RGB signals) or TMS9929 it requires an separated video encoder board which is fairly expensive and complex.

So it's usual that cheaper models use TMS9918 or TMS9118 on their NTSC version.

TMS9118 has also clock out (like V99X8) so you can save more monney with this one

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