1024kb memory upgrade for Yamaha MSX2 YIS503

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By Alexey

Guardian (2446)

Alexey's picture

20-05-2015, 23:53

Replied...

By NYYRIKKI

Enlighted (5398)

NYYRIKKI's picture

21-05-2015, 09:18

Alexey wrote:

The "print inp(&hfe)" command returns 193.

This is very good.

Quote:

Sorry, I can't really recommend anything concerning the expansion of VRAM. I have no knowledge of this kind. You might want to approach someone with a better hardware knowledge: Bas or Nyyrikki.

Here is very good explanation about VRAM expansion and why it is not so great idea than you might think.

By Manuel

Ascended (15819)

Manuel's picture

21-05-2015, 11:52

Can you summarize it, please? Smile

By NYYRIKKI

Enlighted (5398)

NYYRIKKI's picture

21-05-2015, 14:12

- Extra RAM is not usable in SCREEN 7-12
- Possible problems with VDP & VRAM heating up because of incorrect timing.

By gdx

Prophet (3084)

gdx's picture

21-05-2015, 15:17

I have already used the 64KB of 192KB on a MSX in SCREEN7/8 with expanded VRAM.
The only limitation in machine language is that the MSX can not display the page of extra-VRAM.
Thus SETPAGE instruction doesn't support it. Otherwise Extra RAM is also usable in Basic but not easily.

By NYYRIKKI

Enlighted (5398)

NYYRIKKI's picture

21-05-2015, 16:09

gdx wrote:

I have already used the 64KB of 192KB on a MSX in SCREEN7/8 with expanded VRAM.
The only limitation in machine language is that the MSX can not display the page of extra-VRAM.

Well, you can use it, but ie. in SCREEN 8 you get only 128*212 resolution... I consider it a limitation as normally the picture resolution is 256*212. (Two pixels next to each other will have same color)

By Grauw

Ascended (8513)

Grauw's picture

21-05-2015, 19:38

Interesting article, but, the CX5MII (and YIS503II) is an MSX1 machine with V9938 but 16K VRAM. So the VRAM expansion I mentioned was from 16K to 128K, so a completely different matter Smile.

The CX5MII’s RAM and VRAM are mounted as interchangeable modules via header connectors (although there’s also room for it on the main board), and the VRAM header connector has all the signals necessary for 128K (AD0-7 + CAS0/1), so in principle a replacement VRAM board could also be made.

By Jipe

Paragon (1366)

Jipe's picture

21-05-2015, 19:39

see this mod , is for a CX5MII [ and not CX5M (in the title) HansO have translate french to english ]
http://msx.hansotten.com/uploads/msxdocs/yamahacx5m2msx2.pdf

By Alexey

Guardian (2446)

Alexey's picture

31-05-2015, 16:45

One board is still available, just the board, no kit. The price is 4 euros + 2 euro shipment within EU.

Alexey

By Grauw

Ascended (8513)

Grauw's picture

04-06-2015, 00:05

My Yamaha CX5MII now sports a nice 1024K RAM! Smile

If you have a CX-7 motherboard version, the RAM board will work no problem. It’s super-easy to install. Use a small flat screwdriver or pin to pry open the four clamps in the slits on the back side of the machine, and it will open. Then just remove the old RAM module, put in the new one (carefully align pins to the connector), and it’s done!

Now, if someone would make a 128K VRAM module… ;)

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