One Chip MSX Ver.MM

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By RetroTechie

Paragon (1563)

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15-01-2013, 15:04

Would be nice if another batch of 1chipMSX's were built, to drive down ridiculous prices. But I wouldn't hold my breath. Looks more like someone has taken 1chipMSX design files, did a few minor modifications (DC-DC converter, mini SD slot), and sent it off to a pcb prototyping service.

MicroTech wrote:

Can EP1C12 (and consequently EPCS4) be replaced with a EP1C20 (EPCS16) with (very) little effort?

EP1C12 is the biggest Cyclone device in a 240-pin QFP. Devices from same family with more I/O or more LE's are all in BGA housing. Same goes for most devices from newer families like Cyclone II or Cyclone III. There are some in QFP, but those are mostly devices with 'small' number of LE's.

So such an upgrade would involve a significant change to the board layout. Manual soldering would be out, even for a prototype board. Pin assignments (read: probably place-and-route for the FPGA too) would need to be re-done. And in case of a newer family, signal timing would change so you'd basically be porting the 1chipMSX design to a new board (like with DE1 board).

Personally I'd prefer to start with a current device family (say, Cyclone IV), use a ready-made prototyping board (like DE0-Nano) to port the 1chipMSX onto that, and when done, design a new board for the 1chipMSX. But especially prototyping / production of a custom board is very costly (apart from the technical difficulties).

By anonymous

incognito ergo sum (116)

anonymous's picture

15-01-2013, 18:44

KdL wrote:

Bad idea this clone of OCM: the Cyclone is too small always!! No more LEs... No party!! Eek!

Yes, but original OCM is very complete as it is so for most of us and someone that don't want to buy an old MSX computer but only a functional MSX2, it's enough to enjoy in my opinion.

By KdL

Paragon (1415)

KdL's picture

15-01-2013, 23:51

For e.g. when your pc have not free space on hard drive you can replace it...
The Cyclone is very limited and cut me the wings!!

I would integrate other components like V9990 or Moonsound but it's impossible... It's not very good solution!

By nikodr

Paladin (748)

nikodr's picture

16-01-2013, 01:25

What about all of us who would like turbo r or v9990 but cant find a good cheap solution?(sorry i wont pay double or triple prize for the very tiny amount -if any- of turbo r machines present on auctions-)

Can the one chip msx or those clones work as turbo r ?Do they have support for v9990 ?Do they support Leonardo Padial's LPE-Z380 ?
Now that would be cool...By the way does openms support the lpe-z380 ?

By Manuel

Ascended (18405)

Manuel's picture

16-01-2013, 09:18

LPE-Z380 isn't emulated by any emulator. Chicken-and-egg problem: there's practically no software to test with even...


Paladin (846)

WORP3's picture

16-01-2013, 09:25

Possible reason that they choose the old cyclone is that it's 5V compliant, the newer ones aren't. Newer FPGA means more logic, more power requirements,etc,etc.
And if you you choose a to new FPGA, you have to wait for it to get released (FPGA is a year overdue), like me and my Orbit project Sad

By Capitan_Goto

Master (168)

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16-01-2013, 09:52 seems like i was wrong...not so easy to change the Cyclone chip for a more powerful one...Anyway, with the stuff showed in the Korean web, what could be the maximum machine tipe running on it? MSX2? any kind of boosted 2+?

By vanfanel

Champion (446)

vanfanel's picture

16-01-2013, 12:13

A souped-up MSX2+, it is what the 1ChipMSX is nowadays.

By KdL

Paragon (1415)

KdL's picture

16-01-2013, 18:24

1chipMSX it is an emulator in hardware and I think there are not special limits for most implementations at exclusion of the clock speed and to the space ( logic elements, ram, etc ).

By RetroTechie

Paragon (1563)

RetroTechie's picture

16-01-2013, 19:49

WORP3 wrote:

Possible reason that they choose the old cyclone is that it's 5V compliant

No it's not. Cyclone family supports up to 3.3V I/O (and not 5V tolerant!) like most low-end FPGA's, just check the datasheets. IIRC the 1chipMSX simply uses series resistors to limit current when a peripheral outputs 5V. Wouldn't know how much of a 'hack' or safe that is, but seems to work okay.

As for people wanting a Turbo-R clone: 1chipMSX as it is, but with a much higher clocked Z80 would go a long way. Shouldn't require much LE's (if any), bumping up clock speed is pretty much free for a soft core cpu. Big smile I'd guess max Z80 speed is more a limitation of current 1chipMSX design, than a limitation of the Cyclone FPGA. If necessary the few Turbo-R software could be patched to avoid R800-specific instructions so it only needs a fast Z80.

Integrated Gfx9000? Sure, why not, but who really 'needs' that? Just a basic MSX2 with enough RAM and Flash storage is fine for most MSX users, and the 1chipMSX goes way beyond that already. IMHO a bigger FPGA is nice to have, but lower total price is much more important.

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