The VTxxx is a series of system-on-a-chip made by V.R. Technology in Taiwan. Unlike the previous VTxx parts (VT03, VT09, etc), it was not designed with close backwards compatibility with the Famicom in mind. However, the latest parts might have some Famicom compatibility.
- VT168 - supports full 16-bit colour, two background layers, 256x240 resolution. Main CPU and sound CPU both 6502. Known developers include Waxing, Cube Technology, Nice Code, WellMinds and JungleTac. Used in a number of Wii clones including the MiWi 2 and some handhelds. No backwards compatibility other than CPU core with earlier parts. VRT seem to mix it with another part, the VT1682, the difference between the two is not known. Some VT168 ROMs have two bits swapped (7 and 2) in the opcodes.
- VT268 - adds another background layer and a high res 512x240 mode for the sprite layer only, and hardware SD card support. Main CPU is upgraded with 24-bit addressing support. Last VTxxx device with available documentation. Cube Technology list it as one of their platforms. VR Technology suggest it for educational systems, no game consoles confirmed to use it.
- VT368 - used in many newer handhelds and plug-and-plays. Example system on VRT's website shows the JungleTac Classic Max. Other known systems include the Lexibook Retro TV Game console, and several newer DreamGEAR systems. Likely has a degree of backwards compatibility with older chips (VT168, VT03 and FC) as some systems include many games from these platforms too. May have the capability to load games including native and NES ROMs from SD card.
- VT369 - newer than the VT368, neither differences nor systems using it are not known. Some systems listed as VT368 may actually be VT369. Both VT368 and VT369 are listed as systems that WelMinds can develop for.