Article View: comp.robotics
Article #148c64 dc Supply
From: Ryan K. Brooks
Date: Tue, 11 Aug 1992 22:06
Date: Tue, 11 Aug 1992 22:06
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1679 bytes
A few people are wondering about connecting the 64 to a battery, so I thought I'd add my $.02 worth: A few years ago I modified my 64 to take just a regulated 12v signal. As I recall, I desoldered the bridge rectifier, the output pin of the 7812, and the input pin of the 7805. I then ran the +12v to the input (1) of the 7805 and the output (3) of the 7812. This works fine, just make sure the 12v is good since the VIC-II lives on it, and that chip handles your DRAM refresh (so you'll lose more than video). Also, you can remove the SID chip for a small power savings, however then you also lose the analog inputs (along with the sound output, obviously). In BASIC, TI$ and TI will still keep time, but the actual jiffy counters in the CIA will not. I fixed this by dividing a 600 kHz osc down to 60 Hz with some RDD104's, since the 64 normally just generates a TTL square wave off of the 9vac input. All this is easy to do, but I would have to advise against it. The 64 is a hog!!! expect it to draw 2 amps. You could replace the whole thing with a 68hc11 evb (if you know 6502 asm, it is no big deal to learn 6811 and basic is available!) Ryan Brooks - 2575BrooksR@vms.csd.mu.edu NemeSys Corp.
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Path: arc1-ca.pugleaf.net!sparky!uunet!spool.mu.edu!vms.csd.mu.edu!2575BROOKSR From: 2575brooksr@vms.csd.mu.edu (Ryan K. Brooks) Newsgroups: comp.robotics Subject: c64 dc Supply Message-ID: <0095EF10.273E5780@vms.csd.mu.edu> Date: 11 Aug 92 22:06:58 GMT Article-I.D.: vms.0095EF10.273E5780 Sender: news@spool.mu.edu Reply-To: 2575brooksr@vms.csd.mu.edu Organization: Marquette University - Computer Services Lines: 21 Nntp-Posting-Host: vmsf.csd.mu.edu