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Harmony Cart 7800


Underball

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  • 1 month later...
  • 2 weeks later...

If it's too late to request features, I would love a Game Genie style cheats system implemented in the Concerto if patching can be built into the firmware. I came up with a Game Genie code format for Atari:

 

VCS:

 

2k and 4k ROMs - 000:00

bank swapped ROMs - 000:00:00

 

And 7800:

 

16kb and 32Kb ROMs - 0000:00

Bankswapped ROMs - 0000:00:00

 

Unlike Game Genie codes for NES, no funny business with encrypting the codes by moving bytes around. The first group of three hex digits is the address. Conveniently, 16^3 = 4096 so VCS codes can use one less nibble character compared to NES Game Genie. The second group is the byte of data to overwrite the ROM, and the third group is a comparator used for bankswapped ROMs. 7800 codes need to be 6 or 8 characters instead of 5 or 7.

 

Someone correct me if I'm wrong, but do 7800 ROMs loaded off a flash cart need to have a proper checksum? I would imagine they don't because the 7800 boot ROM would only perform a checksum on the flash cart prior to load. Then the flash cart just bank swap it's program for the ROM data when loaded. So barring any sort of soft reset, there would be no reason for the boot ROM to perform a second checksum.

 

Am I on the right page here? Or do ROM patches need to be resigned in order to load off a flash cart? That would throw a monkey wrench into the cheat system.

Edited by stardust4ever
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  • 1 month later...

Someone correct me if I'm wrong, but do 7800 ROMs loaded off a flash cart need to have a proper checksum? I would imagine they don't because the 7800 boot ROM would only perform a checksum on the flash cart prior to load. Then the flash cart just bank swap it's program for the ROM data when loaded. So barring any sort of soft reset, there would be no reason for the boot ROM to perform a second checksum.

 

Am I on the right page here? Or do ROM patches need to be resigned in order to load off a flash cart? That would throw a monkey wrench into the cheat system.

 

No, the ROM's will not have to be signed.

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  • 3 months later...

I have the Harmony for the 2600 but searching the forum, can't find specifics on the 7800 coming to fruition. The website has the Harmony Encore and SD's but only referencing the 2600. What is the lastest word on the projects for the 7800?

Like any homebrew project, be it software or hardware, it'll be done when its done.

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I have the Harmony for the 2600 but searching the forum, can't find specifics on the 7800 coming to fruition. The website has the Harmony Encore and SD's but only referencing the 2600. What is the lastest word on the projects for the 7800?

 

I believe a small first release is planned in October.

 

Mitch

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