GRAEME SMITH                         email: grysmith@freenet.edmonton.ab.ca
YMCA Edmonton

Address has changed with little warning!
(I moved across the hall! :) )

Email will remain constant... at least for now.


On Sat, 8 May 1999, Tim Hamel wrote:

> PICsters,
>
> While we're on the topic of IR, I got a question that's baffled me for some
> time.  I recently hooked up an IR detector (GPU125?) to my parallel port, and
> sampled it.  I was able to rec'v the bit stream, but what I wondered was,
> WHEN do I start sampling?  There are lots of things that I try to master on
> the parallel port -- because the results are instant, and it's easier.  Then
> later I implement it on the PIC.   Anyways, if I start sampling the port TOO
> soon, I'll just get back bunches of 0's, and if it's too late, I might miss
> something.  And as usual, I very much appreciate everyone's knowledge!
>
> Thanks in advance,
>
> Tim H.
>
I don't know all that much about IR....

But isn't that what a "SYNCH" mark does in a HD?

IE.

poll the port until you get some 1's, then test to see how long they
run, (A sync mark is a certain length) if they exceed one byte, you have
found a sync mark, so then continue listening until the RX line goes to
0, and set your frame for future reads.

                                GREY