Need complete list of components necessary to build MSX Compatible computer - Techies needed

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Door Sander

Founder (1871)

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16-01-2009, 01:19

Just for a thought: Image you need to build an MSX Compatible (Note: not necessary a full MSX) computer from scratch. I needs to be dirt cheap. It needs to runs most msx programs.

I was thinking of choosing a design similar to a Philips MSX2 without diskdrive. Maybe with build in compact flash reader and one cartridge port.
But it needs to be ultra cheap. Or is choosing a ASIC solution a better option?

This thing needs to be able to run most MSX programs. I know this hurts, but how much can we strip of our current designs without loosing to much compatibility?

Can we get away with let's say a C-Bios? Or is this not mature enough to replace the MSX-bios? Are there any basic options available that could run most MSX-Basic programs without the need of licensing MSX-Basic? X-Basic? NestorBasic?

Please keep your answers in line with my question. I'll be happy to answer other ones by e-mail. This topic is not created to discuss the value of such a design or our need for it. I really need techies to help here. Non topic discussions: please not here.

Who kicks off?

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Van Leo

Paragon (1236)

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16-01-2009, 05:14

hi ,
MSX can almost be build with standard component , except for the video processor.

standard ics:
Z80A , 8255 , 128kb sram , 128kb flash, a few 74ls139 , 74ls373 , 75LS244 , 74LS245, ...

video ic: v9938 or V9958

keyboard = ??

and some connector for slot cartridge

Van Vampier

Prophet (2409)

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16-01-2009, 06:53

c-bios can't handle basic yet but it can run most carts though.

Van erikmaas

Expert (70)

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16-01-2009, 11:25

I do not see the PSG in the list.

Van mth

Champion (507)

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17-01-2009, 02:30

For large numbers, ASIC is cheapest, but that might be larger numbers than you could ever hope to sell. Or maybe not. Try to find an industry insider for some numbers (not me - I'm a software guy).

FPGA is an option, but then you'd basically end up with a 1-chip-MSX type of design and similar price, which is affordable but not ultra cheap.

Building a machine from the components Leo mentions would work, if you could get your hands on enough VDPs. But soldering a lot of components on a print won't be cheap, as far as I know.

Another option would be to go emulation. Wouter runs openMSX on his GP2X which contains a 200MHz ARM; for most MSX programs that is enough power to run at full frame rate. ARM CPUs are used in most wireless routers, mobile phones etc and some of those are quite cheap. I don't know though if you can actually buy a general purpose ARM + memory controller + LCD controller + generic input pins in a chip, or whether you can only buy the design and still have to have an ASIC produced especially for you.

Regarding C-BIOS: Do you want this new machine to run a known and limited library of programs, or any MSX program thrown at it? Debugging a problem of a particular game with C-BIOS typically takes between 1 and 4 hours and many programs work fine without any fixes, so a library of a couple of hundred programs could be made to run in the order of days. This of course does not include the time a someone would need to learn Z80, MSX or debugging skills.

There is no BASIC for C-BIOS; as far as I know X-Basic and NestorBasic are BASIC accelerators, but require the MSX-BASIC ROM to execute. Probably if you're going to license MSX-BASIC you might as well license the BIOS too, since the address spaces of both overlap: the BIOS is smaller than 16K and part of page 0 is used by BASIC too. Depending on your budget and time-to-market, you could hire someone to write a BASIC for C-BIOS. Several of the BIOS routines needed for BASIC have been written already, so you wouldn't have to start from zero but it would be a significant piece of work. Again, the effort depends a lot on whether it has to run a limited library of programs or every MSX-BASIC program ever written.

Maybe you can ask the people behind the Pandora handheld for info once you've got some more concrete plans. They have designed a small computer from scratch and are bringing it into production. It's more powerful than what you have in mind, but it is produced in relatively modest quantities (about 4000 in the first batch, I think) and by enthusiasts rather than an established electronics company.

But you should probably start by analyzing your market: What would this device enable people to do? How much money is that worth for them? How many can you sell at which price?

Van MäSäXi

Paragon (1884)

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17-01-2009, 14:13

Maybe this question will help people to help you better.

Are you building OLDies computer oldies way so it can only read software made just for it but is partly MSX(1,2,2+,TR) compatible OR are you building some new PC which is somewhat MSX compatible?

Van AuroraMSX

Paragon (1902)

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17-01-2009, 19:05

Ah, I guess dirt cheap in this case means no more than about 20 euro's right? Wink

Van st1mpy

Paladin (900)

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29-01-2009, 17:56

What are insides of the Korean Zemina/Zemmix like? They are probably re-designed cheaply so they might be good to copy, but are they fully MSX compatible?
It's not MSX but what about those small games machines with a joy pad that you can find in some toy shops, that can play Megadrive games with few games built in? They are quite cheap, so it must be possible to do the same with the MSX? (Although I suppose they are counting on selling a lot, and doesn't have slots or keyboard etc...) I am imagining a cheap (>$50) plastic MSX(2+) sold in toy shops, inside a shrink wrapped clear plastic... May be companies like Vtech might be interested?

Van MsxKun

Paragon (1115)

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29-01-2009, 18:14


Another option would be to go emulation. Wouter runs openMSX on his GP2X which contains a 200MHz ARM;

Is some package of openMSX for GP2X available to download? I'd love it, i use GP2X-MSX and works fine, but not perfect Tongue

Van Manuel

Ascended (19270)

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29-01-2009, 20:13

MsxKun: the only way right now is to join the openMSX chat room and ask Wouter. Although it runs fine on Wouter's GP2X, it's still a proof-of-concept thingie...

Van Haohmaru

Paladin (774)

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30-01-2009, 17:34

it's still a proof-of-concept thingie...
True. It does not even remotely run 'fine'. But it works. Sortof Wink

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