Doubts about VT-xx and VT-xxx Specifications and Dev-Tools

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems. See the NESdev wiki for more information.

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BootlegMan
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Doubts about VT-xx and VT-xxx Specifications and Dev-Tools

Post by BootlegMan »

Hello. I'm new to the forum so I hope this thread is being created in the right place. If not, the moderators are free to move it to the appropriate site.

I'm a fan of unlicensed Famicom games and for some time now I've discovered the clone systems of the VT-xx and VT-xxx families. Apparently the VTxx is an early series of systems-on-a-chip created by V.R. Technology. There are five known VTxx chips: VT01, VT02, VT03, VT09, and VT32, all of which are based on the Famicom core, albeit with improved hardware specifications. VTxx variants are used in almost all Famiclones released from the 2000s onward (VTxx hardware was preceded by the UM6578 chip, and would later be followed by the VTxxx hardware line). In the case of VT-xxx unlike previous VTxx chips (VT03, VT09, etc), these were not designed with close backwards compatibility with the Famicom in mind, though they may retain some Famicom compatibility. There are four known VTxx chips: VT-168, VT-268, VT-368 and VT-369.

Given the technical specifications of each system, I was wondering if the development tools currently available for making homebrew for the NES/Famicom could be used to make games for the less demanding systems in the VT-xx family. Likewise, is it known what development tools are being used to make games for both the VT-xx and VT-xxx families?
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Individualised
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Re: Doubts about VT-xx and VT-xxx Specifications and Dev-Tools

Post by Individualised »

The VTxx systems are documented on the NESdev Wiki, that may serve as a starting point. I know homebrew for the VT03 exists but I'm not sure if there has been any attempt at some sort of unified set of development materials for it. Using existing tools for NES development should be possible though, and I imagine adapting them would also be rather easy. There's also a homebrew/"fantasy console" extension to the VT03 which adds things like a second background layer and multiplication/division registers but I'm not sure if it has been supported outside of it's original intended use (for a Super Mario Bros. ROM hack) so I doubt there's any documentation or development materials/tools for that.
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