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From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Basic Stamp vs Pic processors
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <3DA184E7.B1F429F3@webaccess.net> <3DA22778.FD66989F@webaccess.net> <3DA2624E.31F292A4@webaccess.net> <3DA2CF48.457919F3@webaccess.net>
Date: Tue, 08 Oct 2002 15:43:51 GMT
NNTP-Posting-Date: Tue, 08 Oct 2002 08:43:51 PDT
Dave VanHorn wrote:
> > > Interesting. What are you doing that's sucking up 100 AVR mips?
> > DVD focus, tracking, spindle, sledge and some miscellaneous stuff.
> Sounds like fun! I've often wondered how that problem gets solved.
> At any point, did they used to do that with analog?
CD did for sure. The tricky part is initially finding where focus is. I
have to sweep the lens through about 1mm p-p up and down and find a
little S shaped blip about 10 or so microns wide. I have to get the lens
in the middle of that. With analog, the job could be done with a couple
of comparators and some sequence logic to trigger switching to linear
mode (not searching). My thinking in designing the AVR search and grab
for focus was analog. I designed it with a scope capture under my nose.
After focusing, the tracking signal magically appears so the tracking
servo can be told to start. After that, data appears including headers
and we are off to the races.
We never intended to build a working DVD player or writer. We found that
we could show customers data sheets all day long and they wouldn't even
wake up. Now the marketing guy walks in and shows a whole movie and even
the engineers wake up. Go figure. There is some kind of a wow factor
there. Maybe they know how much sweat went into showing just 9 seconds
of video the day we got it to work.
BTW, we do DVD/CD frontend. The backend has a lot of companies doing a
good job of it but the frontend has possibilities.
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons email@example.com
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