Is a space character required at $104?

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MrD
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Is a space character required at $104?

Post by MrD » Thu Feb 20, 2020 4:09 am

'SEGA' is required at $100-$103, but is having a space at $104 required or just convention?

For my Game Raccoon cart, I was considering adding the ability to let games have Game Raccoon-specific functions (basic stuff: 'open a file gametitle_X.sav', 'read byte', 'write byte', 'close file') if they have 'SEGA RACCOON' in the header. Then I wondered if since $0FC-$0FF are never read, you could surround the 'SEGA' with other characters starting at $0FD to spell something like 'MOUSEGAME'. Then I realised that the phrase 'USEGAMERACCOON' would fit perfectly. :D

notaz
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Re: Is a space character required at $104?

Post by notaz » Thu Feb 20, 2020 1:26 pm

Not required, there are some unlicensed games doing exactly what you want to do, like "WISEGAME" for "Funny World & Balloon Boy".

That said I'd suggest you to try to not invent new stuff and reuse protocols of other flashcarts if you can. For SD access there is already MED with it's "extended ssf" protocol for example: http://krikzz.com/pub/support/mega-ever ... ssf-v2.txt

Sik
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Re: Is a space character required at $104?

Post by Sik » Thu Feb 20, 2020 1:37 pm

Only $100-$103 are checked.

That said, not respecting the ROM header is frowned upon so don't do that. Especially since emulators will sometimes rely on the ROM header to detect some stuff (e.g. how much SRAM is installed, or which region to set as default, some may also automatically switch to peripherals like the mouse if supported). See here for details:
https://www.plutiedev.com/rom-header

Also thanks to Sega v. Accolade it shouldn't be illegal to put SEGA in the ROM header :​P (because it's required for interoperability)
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MrD
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Re: Is a space character required at $104?

Post by MrD » Fri Feb 21, 2020 2:08 am

notaz wrote:
Thu Feb 20, 2020 1:26 pm
Not required, there are some unlicensed games doing exactly what you want to do, like "WISEGAME" for "Funny World & Balloon Boy".
That's great, exactly what I wanted to know, thanks :)
That said I'd suggest you to try to not invent new stuff and reuse protocols of other flashcarts if you can. For SD access there is already MED with it's "extended ssf" protocol for example: http://krikzz.com/pub/support/mega-ever ... ssf-v2.txt
It's a bit late for that - plus I was deliberately trying to create something different without looking at what others have done. :) Having a quick look at that, my cart is nowhere near as sophisticated to be able to support all those things, so I'll pass.
Only $100-$103 are checked.

That said, not respecting the ROM header is frowned upon so don't do that. Especially since emulators will sometimes rely on the ROM header to detect some stuff (e.g. how much SRAM is installed, or which region to set as default, some may also automatically switch to peripherals like the mouse if supported). See here for details:
https://www.plutiedev.com/rom-header
This is all great info thanks!
Also thanks to Sega v. Accolade it shouldn't be illegal to put SEGA in the ROM header :​P (because it's required for interoperability)
Wrong country I'm afraid :) also, I found the wikipedia page somewhat hard to follow, I couldn't tell if it was ultimately decided in favour of Sega or Accolade, or left up in the air as a settlement.

Sik
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Re: Is a space character required at $104?

Post by Sik » Fri Feb 21, 2020 2:54 pm

In favor of Accolade (even if eventually Sega decided to just give them a license after that anyway). And other countries tend to be more lenient (turns out most jurisdictions are not happy about actively blocking your competition, especially European ones).

I'd say that the misleading TMSS message on boot is a tad bigger problem than an arbitrary set of bytes that are never displayed to anybody, and the only way to work around that is with extra hardware (to force a 68000 reset on the first access, letting you take over the console before the firmware gets to display its message). The ROM header meanwhile is just what the format spec says.

As for something more relevant to homebrew (as in already became a problem), you should avoid using the Sega logo. It seems to be the main thing Sega cares about nowadays (and has sent several messages around telling people to drop it, because they don't want to be associated with games they had nothing to do with). And if you ask a lawyer, they'll likely tell you to add disclaimers absolutely everywhere you can, just to be safe :​v
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MrD
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Re: Is a space character required at $104?

Post by MrD » Sat Feb 22, 2020 2:41 am

Ah yeah most definitely. I did that for Blast Arena Advance on the GBA in the old days.

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Re: Is a space character required at $104?

Post by Chilly Willy » Sat Feb 22, 2020 12:42 pm

There's also the issue that the word "SEGA" at a set location is probably not creative enough to even qualify for copyright. You can't copyright ANYTHING - it has to be creative and unique. Most countries have requirements about both, with one being that single words cannot qualify for copyright. Trademark, yes, but not copyright. And with trademarks, simply using a trademarked word isn't against the law. Hence why Pepsi can claim in ads to be more popular than Coca Cola, for example. It's only against the law if you use someone else's trademark with the intent of fooling consumers.

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