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RE: Re: [Project] Kbd/LCD device
- To: <ukha_d@xxxxxxx>
- Subject: RE: Re: [Project] Kbd/LCD device
- From: "Dr John Tankard" <john@xxxxxxx>
- Date: Tue, 29 May 2001 16:53:51 +0100
- Delivered-to: rich@xxxxxxx
- Delivered-to: mailing list ukha_d@xxxxxxx
- Mailing-list: list ukha_d@xxxxxxx; contact
ukha_d-owner@xxxxxxx
- Reply-to: ukha_d@xxxxxxx
> I will see if I still have a catalogue I picked up at a trade
> show a couple
> of years ago. They had rotary encoders with a ring of LED's around the
> outside so you could use it to indicate the position a
"manual"
> pot would be
> at before you turned it.
>
VideoLogic DTS decoder uses them, but you have to do about half a turn to
move the led up a notch.
If we were using a graphic LED we could do a moving scale that is activated
when the encoder is moved.
As a subnote, I did a job which required to watch a 360 position encoder
(1440 edges), the encoder was to rotate at about 6 revs per second, I did
the code in FORTH with the decoding as inline assembler and despite my
calculations saying the micro was fast enough it did not work, in the end I
found the problem was the shaft was ending up 6 reves on but it was going
back and forwards several times as well ! To get to the point I added two
HP decoder chips which gave me a 32 bit up down counter, which solved the
problem, It was a HCTL-20XX series works up to 14MHz and does the updown
decoding as well.
John
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