SG-1000 support for the MSX core?

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hyperterminal
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SG-1000 support for the MSX core?

Postby hyperterminal » Wed Jul 25, 2018 5:51 pm

In this thread I wrote that the MSX and SEGA's SG-1000 have similar hardware except for the sound chip.

The current MSX core for the MiSTer is based on the 1chipMSX.

A Japanese programmer wrote a VHDL file to add the SG-1000 sound chip to the 1chipMSX so that both MSX and SG-1000 games can be played (the latter needs a rom loader executed from MSX DOS).

The VDHL file can be downloaded from here: https://www.msx.org/forum/msx-talk/soft ... nd-sg-1000

Would it be possible to add this to the MiSTer core?

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Re: SG-1000 support for the MSX core?

Postby Sorgelig » Thu Jul 26, 2018 8:46 pm

I will look.
Actually SN76489 PSG code is available long time and used in many other cores.
The key point is to integrate SG1000. I don't know MSX hardware and mostly relay on existing code and a few known to me details about MSX HW.
But i will see what can i do.

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Re: SG-1000 support for the MSX core?

Postby bitfan2011 » Sat Dec 29, 2018 5:56 pm

hi

curious about the status of SG-1000 and SC-3000 implementation?
both are getting very obscure and both would be very welcome on MiSTer :]

cheers

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Re: SG-1000 support for the MSX core?

Postby slingshot » Sat Dec 29, 2018 6:06 pm

bitfan2011 wrote:hi

curious about the status of SG-1000 and SC-3000 implementation?
both are getting very obscure and both would be very welcome on MiSTer :]

cheers

Would be much easier to add SG-1000 to the Colecovision core (they're almost the same).

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Re: SG-1000 support for the MSX core?

Postby Gehstock » Sat Dec 29, 2018 8:10 pm

A seperate Core world be the better Decition, for porting to other platforms. It is not much work i have try it but failed but one of you Guys can be Done real quick

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Re: SG-1000 support for the MSX core?

Postby bitfan2011 » Sat Dec 29, 2018 9:42 pm

IIRC a separate SC-3000 & SG-1000 core would be awesome
Still a dedicated fanbase around the world
Some of SEGA's first home games and some very famous developers
Cheers for all your work

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Re: SG-1000 support for the MSX core?

Postby Sorgelig » Sat Dec 29, 2018 10:12 pm

It doesn't matter how many people come here to say "me too".
Need some dedicated developer who will do this and later will be able to fix the bugs.

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Re: SG-1000 support for the MSX core?

Postby slingshot » Sun Jan 06, 2019 11:00 am

It's done:

https://github.com/wsoltys/mist-cores/pull/8

Would be an easy port to MiSTer.

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Re: SG-1000 support for the MSX core?

Postby DrOG » Sun Jan 06, 2019 11:46 am


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Re: SG-1000 support for the MSX core?

Postby Sorgelig » Sun Jan 06, 2019 11:46 am

I'm in process of porting.

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Re: SG-1000 support for the MSX core?

Postby slingshot » Sun Jan 06, 2019 3:16 pm

Sorgelig wrote:I'm in process of porting.

That was fast as usual :)
I'm not sure your Dahjee detection is safe enough, originally I checked the whole RAM area in the ROM file for FF.
Upd.: which I see now that it's somewhat buggy, was too late when I wrote the code :)
Upd2.: I think that's better now: https://github.com/gyurco/mist-cores/co ... d5c9a4b766

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Re: SG-1000 support for the MSX core?

Postby Sorgelig » Sun Jan 06, 2019 3:59 pm

slingshot wrote:I'm not sure your Dahjee detection is safe enough, originally I checked the whole RAM area in the ROM file for FF.
Upd.: which I see now that it's somewhat buggy, was too late when I wrote the code :)
Upd2.: I think that's better now: https://github.com/gyurco/mist-cores/co ... d5c9a4b766

what is Dahjee about, btw?
Are you sure you need to limit romwr_a(15 ..) ? Why don't use higher romwr_a bits?

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Re: SG-1000 support for the MSX core?

Postby slingshot » Sun Jan 06, 2019 4:09 pm

Sorgelig wrote:
slingshot wrote:I'm not sure your Dahjee detection is safe enough, originally I checked the whole RAM area in the ROM file for FF.
Upd.: which I see now that it's somewhat buggy, was too late when I wrote the code :)
Upd2.: I think that's better now: https://github.com/gyurco/mist-cores/co ... d5c9a4b766

what is Dahjee about, btw?
Are you sure you need to limit romwr_a(15 ..) ? Why don't use higher romwr_a bits?


It's just 8k RAM in the ROM area at 2000-3fff. Since the max. size of the SG-1000 roms are 48k, it's not needed to check other bits.

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Re: SG-1000 support for the MSX core?

Postby Sorgelig » Sun Jan 06, 2019 4:12 pm

slingshot wrote:It's just 8k RAM in the ROM area at 2000-3fff

What games use this format?

slingshot wrote:Since the max. size of the SG-1000 roms are 48k, it's not needed to check other bits.

cut the bits to 8x size for easier bit writing. VHDL cons. :)

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Re: SG-1000 support for the MSX core?

Postby Sorgelig » Sun Jan 06, 2019 4:15 pm

ah, ok. Some 48K ROMs may have this hole.

May be it's safe just to leave this area always writable, and then no need to detect it.

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Re: SG-1000 support for the MSX core?

Postby slingshot » Sun Jan 06, 2019 4:24 pm

Sorgelig wrote:ah, ok. Some 48K ROMs may have this hole.

May be it's safe just to leave this area always writable, and then no need to detect it.


Maybe :)
But it would be not simpler to implement, as ROM in SDRAM, RAM in BRAM.

Some games I know about using this:
Knightmare
Tank Battalion
Bomberman Special
Road Fighter
TwinBee

Probably there's a much more complete list on SMSPower site.

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Re: SG-1000 support for the MSX core?

Postby Sorgelig » Sun Jan 06, 2019 4:26 pm

It looks like only around 90 games released for SG1000

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Re: SG-1000 support for the MSX core?

Postby slingshot » Sun Jan 06, 2019 4:57 pm

Seems it wasn't SEGA's most successful console.

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Re: SG-1000 support for the MSX core?

Postby bitfan2011 » Sun Jan 06, 2019 5:32 pm

slingshot wrote:Seems it wasn't SEGA's most successful console.


it actually has an interesting history and includes four different systems
SG-1000
SG-1000 Mark II
Mark III (SMS)
SC-3000

i have all but the original SG-1000, which is surprisingly expensive lately. the funniest thing is how slight the software feels - the cards especially almost feel like they are made of paper.

the SC-3000 still has a global scene, even if it's smaller than some others.


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