Jason Hsu wrote:
> Page 2 of the following document shows two pulses that I need a PIC to
> analyze:
>
http://www.phoenix.tc-ieee.org/0001_Bibliography/2007-05-24%20EMB%20Presentation/2-Carl-Sensors_20070520_Phoenix%20Sensor2.ppt

No, I'm not going to chase down some link to answer a question.  You should
be able to describe the relevant part of the problem in a paragraph here.
If you can't define you're problem in a paragraph or two, then you're not
ready to think about the PIC implementation yet anyway.

> Basically, there are two pulses from two sensors.
> The systolic blood
> pressure we're measuring is a function of the time difference between
> the
> peaks of the two pulses.  The diastolic blood pressure we're
> measuring is a
> function of the time difference between the troughs of the two pulses.
>
> I have never before used a PIC to analyze a pulse.  I'm trying to
> think of
> the best way to do this.

In general a CCP module in capture mode is good for this.  It captures the
free running timer 1 on one of the edges of the pulse.  It's not clear
exactly what you are trying to do, but you probably need at least 2 CCP
modules, one for each pulse.  Quite a few PICs have two CCP.  If you need
more, like one for each edge of each pulse, then look at the dsPICs.  Some
of them have more than two if I remember right.  Note that the peripheral
that does a pulse edge capture on a dsPIC is called "input compare", not
CCP.


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