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Re: Play wav music and sound effect
Posted: Fri Nov 13, 2020 9:57 am
by masteries
Stef wrote: ↑Mon Oct 26, 2015 9:55 am
Actually you can use rom up to 8 MB (even 10 MB with a bit of extra hardware)
without bank switching but if you do it, you are not anymore compatible with Sega CD nor 32X addon. Also you need a specific emulator to handle large rom like that.
Bank switch is the safe and official way to go for rom above 4 MB but then you need to switch bank when you access data > 4MB and you need to write specific code to handle these cases (SGDK do not give tools for that right now).
From this sentence, I have deduced that a 8 megabytes ROM can be created with SGDK, and use it in a MD cartridge without problems.
Is it really true (I am always mind restricted to 4 MB
) ?
This is a new world of possibilities!
Re: Play wav music and sound effect
Posted: Fri Nov 13, 2020 1:15 pm
by Stef
Yeah of course you can, you just need a 8 MB ROM cart for that and it is not recommended to use flat mapping as it eats extension memory space but if don't care about it...
Re: Play wav music and sound effect
Posted: Fri Nov 13, 2020 1:27 pm
by masteries
Stef wrote: ↑Fri Nov 13, 2020 1:15 pm
Yeah of course you can, you just need a 8 MB ROM cart for that and it is not recommended to use flat mapping as it eats extension memory space but if don't care about it...
Thanks Stef!
The intention is to insert as many stuff I can into a single 8 MB ROM chip;
and use the game cartridge on a plain MD / Genesis system, without 32x or Sega CD attached.
(I think these are allocated on the extension memory space).
Re: Play wav music and sound effect
Posted: Fri Nov 13, 2020 11:23 pm
by Sik
The problem with using up all 8MB comes from the fact that it breaks if a Mega CD is plugged in, whether it's being used or not (because the Mega CD will try to respond to its own range). This is true for stuff like Wondermega and CDX as well.
There's a theory that manipulating /CART on the fly could be used to work around it safely (i.e. swapping in which side the cartridge slot is mapped on the fly) but I don't think anybody has actually tested yet if it works. I also don't know if it'd work on a model 3.
Re: Play wav music and sound effect
Posted: Tue Nov 17, 2020 11:22 am
by masteries
Sik wrote: ↑Fri Nov 13, 2020 11:23 pm
The problem with using up all 8MB comes from the fact that it breaks if a Mega CD is plugged in, whether it's being used or not (because the Mega CD will try to respond to its own range). This is true for stuff like Wondermega and CDX as well.
There's a theory that manipulating /CART on the fly could be used to work around it safely (i.e. swapping in which side the cartridge slot is mapped on the fly) but I don't think anybody has actually tested yet if it works. I also don't know if it'd work on a model 3.
Yes, I know that no hardware addons can be connected when using a 8 MB cartridge (that do not use any mapping technique).
Also, are you explaining that probably these 8 MB cartridges will not operate on a plain Genesis model 3?
However, model 3 units are less common than model 2 and model 1.