Can we use SA-1 and FX 1/2

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iNCEPTIONAL

Can we use SA-1 and FX 1/2

Post by iNCEPTIONAL »

Can we use the likes of SA-1 or either of the FX chips in our own SNES carts?

And I presume we can use FastROM and the likes based on the various topic titles, but also just want to double check that's a definite?

At the very least, even if I can't access something like say the SA-1 chip, it would be good to know for sure I can run my game in carts with FastROM and whichever is the better out of LoROM and HiROM (which is the better of those?), maybe with a larger cart size too (say 48Mb).

This is all possible, right?
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: Can we use SA-1 and FX 1/2

Post by lidnariq »

iNCEPTIONAL wrote: Sun Jan 30, 2022 8:37 am Can we use the likes of SA-1 or either of the FX chips in our own SNES carts?
There is no source for new parts here. The closest you can get is the FXPAK, or scavenging parts off existing games. Neither is particularly affordable.
And I presume we can use FastROM and the likes based on the various topic titles, but also just want to double check that's a definite?
FastROM is fine.
At the very least, even if I can't access something like say the SA-1 chip, it would be good to know for sure I can run my game in carts with FastROM and whichever is the better out of LoROM and HiROM (which is the better of those?), maybe with a larger cart size too (say 48Mb).
HiROM is a superset of LoROM.
iNCEPTIONAL

Re: Can we use SA-1 and FX 1/2

Post by iNCEPTIONAL »

lidnariq wrote: Sun Jan 30, 2022 12:29 pm
iNCEPTIONAL wrote: Sun Jan 30, 2022 8:37 am Can we use the likes of SA-1 or either of the FX chips in our own SNES carts?
There is no source for new parts here. The closest you can get is the FXPAK, or scavenging parts off existing games. Neither is particularly affordable.
And I presume we can use FastROM and the likes based on the various topic titles, but also just want to double check that's a definite?
FastROM is fine.
At the very least, even if I can't access something like say the SA-1 chip, it would be good to know for sure I can run my game in carts with FastROM and whichever is the better out of LoROM and HiROM (which is the better of those?), maybe with a larger cart size too (say 48Mb).
HiROM is a superset of LoROM.
Well that's a shame on the first point.

That's good to hear. I think my idea will be fine within the limitations of FastROM.

What do you mean by superset? Which one is better to go with ultimately, or do games use both back and forth depending on the situation?

Ultimately, I guess this is really stuff for a programmer to worry about, but I might as well get an idea so I don't go too crazy with the ideas for my game.
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: Can we use SA-1 and FX 1/2

Post by lidnariq »

iNCEPTIONAL wrote: Sun Jan 30, 2022 1:17 pm What do you mean by superset? Which one is better to go with ultimately, or do games use both back and forth depending on the situation?
HiROM is "we'll use the 64KB in each bank in banks $C0-$FF". LoROM is "we'll use the 32KB in the upper half of each bank in banks $80-$FF".

Each HiROM bank consists of a half that can be accessed as though it were LoROM (banks $80-$BF or banks $C0-$FF, upper half of the address space) and a half that can't be (lower half of the address space, banks $C0-$FF only).
iNCEPTIONAL

Re: Can we use SA-1 and FX 1/2

Post by iNCEPTIONAL »

lidnariq wrote: Sun Jan 30, 2022 1:53 pm
iNCEPTIONAL wrote: Sun Jan 30, 2022 1:17 pm What do you mean by superset? Which one is better to go with ultimately, or do games use both back and forth depending on the situation?
HiROM is "we'll use the 64KB in each bank in banks $C0-$FF". LoROM is "we'll use the 32KB in the upper half of each bank in banks $80-$FF".

Each HiROM bank consists of a half that can be accessed as though it were LoROM (banks $80-$BF or banks $C0-$FF, upper half of the address space) and a half that can't be (lower half of the address space, banks $C0-$FF only).
So, HiROM is more versatile, yes? Does that make it better? I honestly don't understand anything above other than there's some hex values (which I can't read) and it seems LowROM has only one option of where to put something and HiROM has two options of where to put something, or something like that. I'm a total programming noob, so trying to understand things in the most layman terms.
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: Can we use SA-1 and FX 1/2

Post by lidnariq »

The approximate answer is: LoROM vs HiROM doesn't matter at all for the layman. With only a few exceptions, it doesn't matter where in ROM things are. Those exceptions require more background knowledge than you have in order to be worth explaining.
iNCEPTIONAL

Re: Can we use SA-1 and FX 1/2

Post by iNCEPTIONAL »

lidnariq wrote: Sun Jan 30, 2022 3:37 pm The approximate answer is: LoROM vs HiROM doesn't matter at all for the layman. With only a few exceptions, it doesn't matter where in ROM things are. Those exceptions require more background knowledge than you have in order to be worth explaining.
So, basically, if I'm making a SNES game that at some point I want to release as a physical cartridge, I don't have to worry myself with whether it's going to use LoRom or HiRom? It doesn't have any potential impact on how much performance I can squeeze out of the stock SNES [plus FastROM] with whatever one I go with?
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: Can we use SA-1 and FX 1/2

Post by lidnariq »

This is something for the programmer to figure out once they get to that point. If you're the programmer but you're not at that point, making a decision is like deciding that you'll paint your future house blue.

There are reasons for both, and eventually you may encounter them. Knowing those reasons now won't help you make a decision now, because your questions indicate that you don't have enough code or assets generated yet for it to matter.
calima
Posts: 1745
Joined: Tue Oct 06, 2015 10:16 am

Re: Can we use SA-1 and FX 1/2

Post by calima »

None of the expansion chips are available for repros, but as you can see in Vitor's SA-1 conversions and those that enable FastROM only, a shmup doesn't necessarily need the expansion.

You didn't directly ask about this, but I feel it's relevant. If you were to hire MegaCat for the programming (and possibly audio, manufacturing, distribution etc), we do LoROM games up to 2mb. Various compression is available, depending on game needs etc, so how much you can pack into 2mb also varies.

If you do a reasonably complete proto in GameMaker, follow all the art restrictions, that's a good start and shows what you're after.
iNCEPTIONAL

Re: Can we use SA-1 and FX 1/2

Post by iNCEPTIONAL »

calima wrote: Mon Jan 31, 2022 1:57 am None of the expansion chips are available for repros, but as you can see in Vitor's SA-1 conversions and those that enable FastROM only, a shmup doesn't necessarily need the expansion.

You didn't directly ask about this, but I feel it's relevant. If you were to hire MegaCat for the programming (and possibly audio, manufacturing, distribution etc), we do LoROM games up to 2mb. Various compression is available, depending on game needs etc, so how much you can pack into 2mb also varies.

If you do a reasonably complete proto in GameMaker, follow all the art restrictions, that's a good start and shows what you're after.
Great, I'll keep this in mind going forward. I'm not really sure now what spec of cart I'd need, like the size for example, but I'll see how the game turns out and figure that out down the line.

Do you do higher spec carts and stuff as well? I mean, if it came to it, I'd want to make sure there was no good reason to either limit my game in scope/features or worry about it suffering slowdown and the like if not necessary, since I'm technically not restricted by things like time and budget as developers probably were all the time in the past, so I'd be looking at whatever cart makes the game the best it can be yet without adding unnecessary tech that's not going to be use anyway.
iNCEPTIONAL

Re: Can we use SA-1 and FX 1/2

Post by iNCEPTIONAL »

lidnariq wrote: Sun Jan 30, 2022 5:57 pm This is something for the programmer to figure out once they get to that point. If you're the programmer but you're not at that point, making a decision is like deciding that you'll paint your future house blue.

There are reasons for both, and eventually you may encounter them. Knowing those reasons now won't help you make a decision now, because your questions indicate that you don't have enough code or assets generated yet for it to matter.
Cool cool.
calima
Posts: 1745
Joined: Tue Oct 06, 2015 10:16 am

Re: Can we use SA-1 and FX 1/2

Post by calima »

Higher spec carts as in? The expansion chips aren't available, and FastROM is the default nowadays. Cart size does not affect speed in any way.

Bigger carts can probably be arranged.
iNCEPTIONAL

Re: Can we use SA-1 and FX 1/2

Post by iNCEPTIONAL »

calima wrote: Mon Jan 31, 2022 9:50 am Higher spec carts as in? The expansion chips aren't available, and FastROM is the default nowadays. Cart size does not affect speed in any way.

Bigger carts can probably be arranged.
Yeah, it was basically just the FastROM and large cart size (if necessary), so all good. :D
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