> Dear all, are few days I'm in trouble with the following problem:
> how to produce pulses bursts (from 5 portb of a 16f84 4 MHz) starting
> from the same instant.
> The number of pulses for each port can change from 0 to 65535, the
> pulses freq can be any, the repetition rate of the bursts is 10 sec(from
> an external trig).
> I've tried to implement sorting routines but I realized to be too heavy,
> more I tougth to produce a mask of the port  in W, decreasing for 1 any
> of the 5 words checking to Z and setting to 0 the relative bit in W
> putting out W and more settingW to all 1s  putting out it again; this
> approach seems to me too time expensive.
> This is a part of a project for a balloon borne experiment.
> I'm sorry for my awful english, please be patient and "grazie" for any
> suggestion.

I couldn't follow all you were trying to say, but you can toggle a bunch of
port bits at once using the XORWF instruction.  If the burst only needs to
be a few cycles long, you can inline a bunch of XORWF instructions and get
an output frequency of oscillator/8.  Longer bursts require a loop which
would slow down the output frequency.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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