At 02:03 PM 02/09/2011, you wrote:
>I am not sure if this warrants EE or PIC subject tags, but here goes...
>
>I am building a hobby gadget around an 18F2321, it is running on
>INTOSC+PLL for a 32MHz clock. My main UI element is a quadrature encoded
>knob from BI Technologies (data sheet here
>http://www.bitechnologies.com/pdfs/en11.pdf). From the datasheet there
>appear to be 2 mechanical switches that connect to the common pin to
>provide the output. I have grounded the common pin, and the two outputs
>are connected directly to the RB0 and RB1 on the PIC. The weak pull ups
>are turned on.
>
>My original idea was to use INT0 as a movement indicator then read PORTB.1
>(a TTL input) to determine direction. While this very accurately
>determined rotation, the direction of rotation was very flaky with either
>direction providing equally random results.
>
>My guess at this point are that the switches are bouncing...
>
>I did some googling to try and determine what I could do to help clean up
>the signal. Most everything I have read shows a capacitor in parallel with
>the switch, but without an actual value associated (I tried ~15nF without
>any success). I have also read that a schmitt trigger will help, so I
>switched to using INT1 with a mechanism to use INTEDG1 to store the pin
>state, this wasn't much help either.
>
>I am at a loss to what to try next, and hoping that the smart folks on
>this list have some better ideas...
>
>Anthony

Forget using interrupts. Poll it at a few hundred Hz.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the rewar=
d"
speff@interlog.com             Info for manufacturers: http://www.trexon.co=
m
Embedded software/hardware/analog  Info for designers:  http://www.speff.co=
m



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