Message-ID: <011701bf2e8a$9c12b720$0200a8c0@test>
From: "Dave Brown" <tractorb@ihug.co.nz>
To: rsgb_lf_group@blacksheep.org
References: <199911140337_MC2-8CFC-355C@compuserve.com>
Subject: LF: Re: Question: Rotating Shift Encoder
Date: Sun, 14 Nov 1999 23:25:39 +1300
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Geri
Simple shaft encoders use two identical pulse trains, say A and B,  from the
encoder that are 90 degrees apart in time. That way the direction of turning
can be detected depending on whether the A pulse is output before the B
pulse.  If your circuit has two data lines going into the PIC (not counting
ground and logic power supply lines) then it is probably one of these.

Grounding the A input then the B input should make the frequency go one way
(say up) and doing the opposite, grounding the B input and then the A input
should  make the frequency go back (go down).

 If this works then you can make a simple logic circuit to do it but beware
of trying to do it too fast. The DDS may not be able to respond at 45 bauds?

 Hope this helps.
73
Dave
ZL3FJ