Strange cartridge

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

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krzysiobal
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Strange cartridge

Post by krzysiobal »

What's that? Even no CHR chip?
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Bavi_H
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Re: Strange cartridge

Post by Bavi_H »

Could it be a prototype Game Genie?

In the Game Genie patent, the first diagrams are of a double-ended cartridge with six 16-position dials on it, presumably a manual way of entering a 6-letter Game Genie code.

The Game Genie has no CHR ROM, it generates sixteen different "chunky pixel" tile patterns based on the CHR address requested, this method is also mentioned in the patent.
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krzysiobal
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Re: Strange cartridge

Post by krzysiobal »

Hmm, looking at this poor quality picture I see the CHR pins are not connected to anything at all.
So I assume either the cartridge does not display anything or.. uses console internal VRAM as chr-ram ?
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tepples
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Re: Strange cartridge

Post by tepples »

Game Genie appears to make a makeshift CHR ROM out of a multiplexer selected by A2 on the PPU bus. In the top half of each character (A2=0), the circuit generates D7-D4 and D3-D0 from two bits in the address, and in the bottom half (A2=1), it generates D7-D4 and D3-D0 from two other bits.
q5911
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Re: Strange cartridge

Post by q5911 »

This is a karaoke cartridge for one of the FC machines (called learning machines in China) made in China.
I don't know what model it is.What is certain is that VRAM is built into the machine, similar to SUBOR 97.
I got this cartridge once.And mapping schematic diagram, save ROM data.I'll post it here if you want.

Cartridges of interest.
viewtopic.php?t=18248&start=15
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