|The 6502 & 6560 both run full speed!|
Bill along with John Feagans, put together a 6560-based computer after some preliminary discussions with Bob, just for fun. Bill pulled one of Commodores old printing calculators from the trash. He removed the calculator guts and modified the case to take the original small PET keyboard and then modified a PET mother board to fit inside. He sawed the PET mother board in half, removing the video section. He replaced the video section with the 6560 graphics chip. With the help of John they patched the system ROMs from the PET to use the 6560 for video display. John said, "I made the ROM software modular in anticipation of the hardware."
|6560 output adjustments|
Visiting The VIC-20 Video
by Jim Butterfield, Associate Editor, COMPUTE! ISSUES #36, #37, #38 and #39
...In which the traveler discovers a new way of viewing the computer's memory: through a video chip. This is a four-part series about the structure and uses of the VIC's video chip. If we want to put the VIC-20 video chip to work, we must learn to see things from its standpoint. It sees the computer memory in a way that differs significantly from the way the processor chip sees it...The 6561 die shot below is stitched from many separate microscope shots by Greg James using a Nikon LV150 with an LU Plan Fluor 20x objective. The images were corrected and stitched automatically by Christian Sattler in the UK, using Autopano-sift-C and custom code.
1600 x 1622 PNG 5.7 mb
6500 x 6588 PNG 77.7 mb
By 1982, Al would be Vice President of Engineering at Commodore, where he led the development team responsible for the Commodore 64, including the VIC-II (video) and SID (sound) integrated circuits. The C64 had barely made it out the door in 1983 when five of its six principal engineers: Al Charpentier, designer of the VIC and VIC-II video interface chips; Bob Yannes, designer of the MicroPET and SID sound interface device; Charles Winterable; David Ziembeicki and Bruce Crockette, all left Commodore and started Peripheral Visions -- which was quickly renamed Ensoniq. Their first product was a software drum machine that ran on home computers manufactured by Commodore competitor, Atari.
Ironically, the year the EPA shut them down matches the model number of Commodore's first computer developed at MOS, the PET 2001 (which itself was a reference to a movie of the same name). Great Mixed-signal Technologies was forced to cease operations and then liquidated. That's quite an odyssey!
I have an additional VIC-20 blog entry: Wednesday, January 2, 2013 - Turning Japanese...
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