F4/FMPAC Light Combo Board project

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By Alexey

Guardian (2000)

Alexey's picture

22-07-2015, 19:07

madscient wrote:

Really interesting. I want to buy at least 20 pcs if you can sell!

We have some technical difficulties now. The board works, but something is not right, so we are investigating. When the problems are solved, I will let you know. There will be a new (fixed) board anyway.

By madscient

Master (177)

madscient's picture

22-07-2015, 20:39

Alexey wrote:

We have some technical difficulties now. The board works, but something is not right, so we are investigating. When the problems are solved, I will let you know. There will be a new (fixed) board anyway.

I have found a problem in the schematics.
/WE of YM2413 should be dropped into ground, use /CS for write control instead.

FYI:
http://madscient.hatenablog.jp/entry/2013/06/06/120140

By Alexey

Guardian (2000)

Alexey's picture

22-07-2015, 21:26

madscient wrote:

I have found a problem in the schematics. /WE of YM2413 should be dropped into ground, use /CS for write control instead.

All FMPAC schematics have WR connected to WE of 2413. Our board works fine, but there are some other, probably power-related troubles. We are investigating.

By madscient

Master (177)

madscient's picture

22-07-2015, 21:58

Alexey wrote:

All FMPAC schematics have WR connected to WE of 2413. Our board works fine, but there are some other, probably power-related troubles. We are investigating.

Oh, it's good.
I was talking about FMPAC schematics I saw:
http://www.geocities.jp/atx197/FMPAC_02a.pdf

By NYYRIKKI

Enlighted (5210)

NYYRIKKI's picture

23-07-2015, 21:21

If you can get it working and you make ready assembled board, I have only one thing to say...

Shut up, and take my money!

By Alexey

Guardian (2000)

Alexey's picture

23-07-2015, 21:46

NYYRIKKI wrote:

If you can get it working and you make ready assembled board, I have only one thing to say...
Shut up, and take my money!

We have the board ready. There's a minor design fault there that can be easily fixed or simply ignored. The board works, both amplifier parts work as they should, the sound is great... But something is not right with the MSX where it is installed - it freezes. We suspect a power related problem. We are now investigating whether this is a bad soldering issue or a nastier design fault...

By DJs3000

Expert (104)

DJs3000's picture

01-08-2015, 16:04

By Grauw

Enlighted (7897)

Grauw's picture

01-08-2015, 17:49

Nice! Why did it restart with less RAM?

p.s. I see the YIS503IIIR doesn’t have that little front slot that my CX5MII has Smile.

By Alexey

Guardian (2000)

Alexey's picture

09-08-2015, 09:21

We are going to put an optional ROM chip on board as old games don't seem to detect FMPAC without BIOS. Also Dmitry will try to add FMPAC BIOS to the additional ROM image on the modified Yamaha MSX2+. There's 16kb free space there.

By Alexey

Guardian (2000)

Alexey's picture

10-08-2015, 03:03

The board layout with the optional FMPAC ROM is ready. On the schematics that we have the ROM is connected to CS1 and SLTSEL pins of a slot. So my question to Jipe and other hardware gurus is: can this board conflict with any cartridges inserted into MSX slots?

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