On 11/02/2011 02:12 PM, Richard Atkinson wrote: > (Incidentally as yet another aside, I wonder how the > 6560/6561 VIC-I chrominance encoding works, as it predates this patent, and > in the case of the 6561 it only receives PAL subcarrier frequencies at 1x > subcarrier frequency) You sure about that? According to http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/vic20/324001_1.gif the PAL VIC in the VC-20 uses a Crystal at twice PAL clock and the chip has 2 clock inputs, one of them is the clock after being run through a 74LS74. Makes me wonder if they did some dirty tricks with this. The NTSC-VIC uses the normal 14.318MHz crystal (according to the schematic). Also, even though the 6560 is older than the patent, as far as I know they did backport some of the things they learned when designing the ill fated 6562 to the 6560/61. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2011-11-02 18:00:21
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