Colecovision > MSX | MSX Resource Center (Страница 11/26)

By Grauw

Ascended (10821)

20-03-2014, 22:39

Looks sweet! I’ll take one (NL).

By jltursan

Prophet (2619)

20-03-2014, 23:18

Count me in, I want one!

By msxrestarter

Master (224)

21-03-2014, 00:50

Looks great, I want one !

By gdx

Enlighted (6438)

21-03-2014, 04:54

ericb59,

The version of Pepper II from Muffie has some bugs in GFX and some sound effects have missing. It's not a good idea to put this version in a cartridge.

hbarcellos,

My work is based on Mission at start. At first I debugged and improved all Mission routines. Graphic and input routines are very different now. Sound routines have little changed. I also modified the interrupt routine (that I do not yet fully understand).

My process is as follows:

Of course I seek all access to the VDP to ports (IN, OUT, IN _,(C), OUT (C),_ INI, OUTI, IND, OUTD, INIR, OTIR, INDR, OTDR), joystick and sound calls in game ROM.
If the game still does not work properly then I place DI & EI instructions in sensitive areas. I also try to optimize some routines.
If the game still does not work properly again maybe it is caused by register mirrors, RAM address mirrors or interruptions problem.

The differences between ColecoVision and MSX harware:

ColecoVision

Main interrruptions are /NMI (caused by the VDP)
VDP it is same that MSX1 but I/O access is #BE/#BF (the mirrors do not seem to use)
Joystick status: It is easy. Write any value to #80 or #C0 and read port #FC or #FF. (Be careful at mirrors)
Sound chip: It is a SN76489AN. PSG with 3 sound voices + 1 noise voice. Used port is generally #F0 but there are mirrors used. Sound routines must replace some OUT of the Colecovision.

MSX

All interrruptions are /INT
VDP I/O ports is #98/#98 (Be careful at register mirrors that do not exist on V9938/V9958)
Input status: To play converted games on MSX, We need use keyboard and optionally joysticks. This is managed in the interrupt routine in Mission.
Sound chip: It is a AY-3-8910 (or a YM2149). It is a different PSG with 3 sound/noise voices.

The biggest problem is to adapt a /NMI to /INT configuration. Sound and input routines shift the progress of the program.

Where can I find your source code? Perhaps We can do better with our combined work. Perhaps it is possible to mix 3 PSG voices + 1 SCC voice. Mission use 3 PSG voices or 4 SCC voices. Only the following games use 3 voices on ColecoVision:

Donkey Kong
Donkey Kong Jr.
Mr. Do!
Roc'n Rope
Sammy Lightfoot

By andrea.denara

Expert (73)

21-03-2014, 08:44

Hi,
please take a look to
http://www.youtube.com/watch?v=vqFG_SGw6n8
this is Coleco PacMan prototype.
It's a must have for me, first of all is Atari game, second there's more than 4 sprites without flickering on the same line.
Unfortunately it doesn't go on Mission emulator.
If someone has some ideas to run it on a Msx....

Thanks

By hbarcellos

Hero (649)

21-03-2014, 13:23

@gdx
Here's the source code. You can find the SN emulator and the Keyboard/Joystick routines there. Let me know if it's working.
I converted Pepper 2 in 1 (one) day. Using the package that I had created for Tutanhkham.
I really don't believe there are sounds missing. Probably what happened is that noises sound like regular tones, but, as far as I can remember, there's nothing missing.
About the GFX bugs, can you give me some example? I would love to fix those before Eric ships the cart...

@andrea.denara
Do you have the Coleco ROM? Can you send me...

By ericb59

Paragon (1126)

21-03-2014, 13:47

Just one thing… In the aim of building a Cartridge set with other coleco Games, using SCC sound chip is not a good idea.
Because if you use SCC chip, you must use a SCC chip in the same slot as the ROM… Thus, in the same cartridge !
At this moment... the only way to do this is butcher Konami SCC cartridge ! No way for me !

By Manuel

Ascended (19683)

21-03-2014, 18:02

You may also find some (new) old stock of Konami SCC chips. The original Mega Flash ROM SCC was made with them.

By gdx

Enlighted (6438)

22-03-2014, 03:37

Thank hbarcellos (Miffie ? andrea.denara ?) for the source code.

hbarcellos wrote:

About the GFX bugs, can you give me some example? I would love to fix those before Eric ships the cart...

The GFX bugs occur randomly when a stage display. Sometimes some characters appear at wrong place.

It even happens that the stage can not be clear because of it.

I had the same problem with several games. This is a problem of interruptions.

hbarcellos wrote:

Do you have the Coleco ROM? Can you send me...

I send it soon (with my conversion).

PS: Pepper II uses little the fourth voice so it is not very annoying..

ericb59 wrote:

Just one thing… In the aim of building a Cartridge set with other coleco Games, using SCC sound chip is not a good idea.
Because if you use SCC chip, you must use a SCC chip in the same slot as the ROM… Thus, in the same cartridge !
At this moment... the only way to do this is butcher Konami SCC cartridge ! No way for me !

I agree. If we exclude the SN76489AN I think the best way is a mix of 3 PSG voices and a optional SCC voice for the noise (A voice played by a SCC cartridge in another port.).

There are other more complicated solution: Switching a voice of AY-3-8910 when there is a noise.

By gdx

Enlighted (6438)

22-03-2014, 05:21

gdx wrote:

PS: Pepper II uses little the fourth voice so it is not very annoying.

I was wrong. Peper II does not use the noise voice. I left the SCC sound in my conversion because I thought the music less aggressive thereby.