11 Jun
2013
11 Jun
'13
9:17 a.m.
Hi,
I'd assume you're thinking along the lines of
a simple digital PLL
using the capture/compare functions of the timers? That could be
done with a VERY small AVR/other micro indeed.
I think of doing it interrupt driven
in software :-)
I already made some rough estimations on the timings involved.
If you wanted to make it more "retro", you
might be able to do it
fairly simply with a 6502 and 6522. :-) Still more modern than
the RK05's internals, though, and I have no idea how much space
is available in the box there.
I will use a 20MHz ATmega-AVR ATmega48 or ATmega88.
The reason is that I already
have that part. It's available for less than EUR 3 and does the job. I know it's
overkill. But I'm not designing for mass-production where every penny costs
thousands.
I want to get the job DONE and the thing RUNNING.
So I use the MCU that I have on stock and where I already have made some
schematic templates in Eagle.
Everyone who wants it "more retro" is free to do so. But why has it not been
done yet??? :-P
Some prophylactic info: I will *NOT* use any special magic driver IC for the
generated index pulse output. A regular AVR pin has to do the open collector job.
I will *now* play a bit with a TU56 drive because there's a bit DECtaoe
frustration. When I have finished that I will go back to my Eagle. And I will
probably finish AND BUILD my little board prototype tonight. So it could be up
and running in the next few days. If nothing keeps me from doing so...
Kind regards
Philipp :-)
--
Dipl.-Inf. (FH) Philipp Hachtmann
Buchdruck, Bleisatz, Spezialit?ten
Alemannstr. 21, D-30165 Hannover
Tel. 0511/3522222, Mobil 0171/2632239
Fax. 0511/3500439
hachti at hachti.de
www.tiegeldruck.de
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