MOS Technology VIC-II
MOS Technology VIC-II
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MOS Technology VIC-II

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MOS Technology VIC-II

The VIC-II (Video Interface Chip II), specifically known as the MOS Technology 6567/6566/8562/8564 (NTSC versions), 6569/8565/8566 (PAL), is the microchip tasked with generating Y/C video signals (combined to composite video in the RF modulator) and DRAM refresh signals in the Commodore 64 and Commodore 128 home computers.

Succeeding the original MOS Technology VIC used in the VIC-20, the VIC-II was one of the key custom chips in the Commodore 64 (the other being the MOS Technology 6581 sound chip).

The VIC-II chip was designed primarily by Albert Charpentier and Charles Winterble at MOS Technology, Inc. as a successor to the MOS Technology 6560 "VIC". The team at MOS Technology had previously failed to produce two graphics chips named MOS Technology 6562 for the Commodore TOI computer, and MOS Technology 6564 for the Color PET, due to memory speed constraints.

In order to construct the VIC-II, Charpentier and Winterble made a market survey of current home computers and video games, listing up the current features, and what features they wanted to have in the VIC-II. The idea of adding sprites came from the TI-99/4A computer and its TMS9918 graphics coprocessor. The idea to support collision detection came from the Mattel Intellivision. The Atari 800 was also mined for desired features, particularly bitmap mode, which was a desired goal of the MOS team as all of Commodore's principal home computer rivals had bitmap graphics while the VIC-20 only had redefinable characters. About 3/4 of the chip surface is used for the sprite functionality.

The chip was partly laid out using electronic design automation tools from Applicon (now a part of UGS Corp.), and partly laid out manually on vellum paper. The design was partly debugged by fabricating chips containing small subsets of the design, which could then be tested separately. This was easy since MOS Technology had both its research and development lab and semiconductor plant at the same location. The initial batch of test chips came out almost fully functional, with only one bad sprite. The chip was developed in 5 micrometer technology.

The work on the VIC-II was completed in November 1981 while Robert Yannes was simultaneously working on the SID chip. Both chips, like the Commodore 64, were finished in time for the Consumer Electronics Show in the first weekend of January 1982.

Some of the graphics modes on the 64 are really strange, and they have no analogs to the Atari or Apple, like the ability to change color of the character basis across the screen. That gave us a lot of color capability that had not been exploited.

— Craig Nelson of Epyx, 1986

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