Soon I will receive the new TMTLogic MSX graphics cartridge. This time it will be harder for me to make it work on the Enterprise, because this beast has to be programmed entirely by IN and OUT Z80 commands. At least I already have the M-Slot, so I don't have to struggle thinking how to connect it to our computer... There is an old V9990 library that can aid us to make new programs.

The story of this GFX-NINE cartridge is similar to the story of the SE-ONE, it is a clone of a cartridge also designed by Sunrise, a group of Swish and Dutch MSX developers on mid 90s.  Its name was GFX-9000, and was the last amateur attempt to update the MSX hardware on times where the Amigas and Atari STs where the sovereigns.

The legend says that the Yamaha V9990 chip is a cut-down version of the V9978, the VDP chip (Video Display Processor) designed for the MSX3 series of computers, never released.

Yamaha offered evaluation boards of the chip for MSX and PC systems.

From my own point of view, this chip was a total failure for Yamaha, as I haven't found any device  built around it except this type of add-on cartridges. Not surprisingly it is easy to find full batches of new chips on China.

Sunrise made their GFX-9000 cartridges as cut-down versions of the Evaluation boards, as can be  understood from this early document.

My interest with this special type of MSX cartridges is that they effectively work on an Enterprise, and secondly that they where supported by Prodatron from the first time. There is a V9990 version of SymbOS for MSX computers and, since the last year, a beta for the CPC series. Now it is possible to have our own V9990 version of SymbOS, the fastest, if run on a 10Mhz Enterprise....  

As on the luxurious SE-ONE, Hans has not merely copied the Sunrise cartridge, he has overcome the problems of the circuits with a logic analyser, also redesigning the card to fit on a  low profile case.

Somebody can say, "this will be no more an Enterprise", but I think the contrary, our loved computer can be this powerful, new and old at the same time.

I do know it is most probably dirty nitpicking, but I think you meant external not outsider.

I have a V9990 Powergraph Light from Technobytes. A really powerful piece of kit.

Here is a impressive video of Ghost and Goblins that is coming to MSX and maybe some day EP?.

The GFX-NINE is a totally compatible product, but made in Europe so, no customs and less cost on postage for us.

Is really good that Ghost and Goblins conversion.

The differences between MSX computers and Enterprise are on the memory management and the massive storage management. The floppy format  is FAT12 on both computers.

But the cartridge control is exactly the same, on the same Z80 ports, so there is a lot of work already done in conversions.

I got it!

Tests with this cartridge will take a while...

As an improved clone of the original Graphics9000 from Sunrise, it has been made for the MSX slot, that has its particularities. In my humble attempt I assumed that a straight rearrangement of the Z80 signals would be enough. In fact the actual design of the M-Slot  works very well with the SE-ONE. But some devices are prone to RF interferences, and the V9990 VDP chip seems to be one of them.

I received the GFX-NINE cartridge on earlier September, and from the first time it made unstable my Enterprise, prone to hang it or even not allowing it to start. I thought that some garbage was being written on the Enterprise Bus data, but seeing the graphic cartridge working perfectly on three different MSX computers was annoying... Geco aided me converting some programs from MSX machine code source but it didn't work.

Until the last two weeks I have not figured what was the problem. The V9990 chip is straightly connected to the Z80 Data bus on the Enterprise approach, but searching schematics of MSX computers and classic Enterprise expansions, I discovered that the MSX slot is internally isolated with a 74SL245 gate, that closes or opens the Data bus only when the Z80 access it, allowing only a direction when reading or writing.

Then I have observed the same chip on the classic Enterprise expansions, even on the Floppy controller. I then remembered asking  Zozo about the chip in a far-far past.

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A week ago I made an experiment with one of my spare M-Slot cards, soldering some leads and a little strip board intercalated with a 74LS245 gate on the Data bus, and all the problems ceased abruptly. Then I told it to Hans, and he confirmed my suppositions and advised me on to selecting the proper signals to trigger the chip.

Now I am on the next stage, trying to access the V9990 chip. It seems to obey me, but I am not enough skilled on Z80 machine code, so I am translating the G9k lib to basic, to make the tests more easy for me.

So, better don't connect any GFX-NINE  to your Enterprise through the M-Slot. It will not break your computer, but is a pain to see its behaviour...

All is not lost with the actual version of the M-Slot, as it works perfectly with the SE-ONE and the Philips NMS-1205 Music-Module, but soon I will announce a new improved version.

So, I am actually translating the Team-Bomba G9K lib to IS-Basic but it has still a lot of errors. Meanwhile I have achieved to see the first reaction of the graphics cartridge:

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I told you, I have a skilled friend who owns a Rigol oscilloscope and an Enterprise, but he is always busy. We have to find time to hunt that /RD glitch.

Yes, on the enhanced M-Slot I will use LS(as on the picture), probably a SMD to maintain the aspect. Also on the bus expander I have used LS chips on big SMD format. Is still easy to solder them by hand.

Wow! It's alive

The V9990 has some internal procedures  called commands, that allow simple tasks to be performed very fast, like to draw boxes, lines, points, write text, move data or graphic zones  between the Z80 memory and the 512KB video memory, etc. These commands allow boolean operations.

A loop of random lines:

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Some lines have a S shape...