ecvt or similar will also be very slow since it must do a _lot_ of floating
point arithmetic. Again: get away from floats in the PIC!

~ Bob Ammerman
RAm Systems

> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> Of James Cameron
> Sent: Thursday, November 06, 2014 6:54 AM
> To: Microcontroller discussion list - Public.
> Subject: Re: [PIC]
>=20
> On Thu, Nov 06, 2014 at 12:41:20PM +0100, Tam=E1s Fekete wrote:
> > Hi everyone!
> > I am not sure if this problem is related to this topic. But I don't
> > know where else it would fit.
> >  I am using a dspic33fj128mc802 with mplab xc16 compiler. I have to
> > read data from an ADC at about 1ms intervals. The data that I get is a
> > floating point number. I convert this number into a string using the
> > function sprintf. Send out the string. At the PC side I receive and
> > save the data with putty.exe. Then save the session in a .dat file. I
> > can use this .dat file with matlab to plot the results.
> >
> > The problem is that sprintf really slows down the process. I should be
> > taking samples at about 1ms intervals and because of the sprintf
> > function this is between 5-7 mseconds. I checked this with an
> > oscilloscope and without the sprintf function I can get down to even
> > less than 1ms intervals easily.
> >
> > If anybody could suggest a faster way to make a string out of a
> > floating point number or another way to send and receive the data I
> > would be very thankful.
>=20
> Yes, I've had sprintf take all the time it likes.
>=20
> What I would do is read the data from ADC registers and either transmit i=
t
as
> is, or encode it as hexadecimal.  Then do the conversion on the PC side.
>=20
> But I don't know that chip, so I can't be specific.
>=20
> Also, I don't know the compiler or library you mention, so I don't know
what
> other functions might be available.  I would check for ecvt or some
> equivalent, and compare conversion time against sprintf.
>=20
> --
> James Cameron
> http://quozl.linux.org.au/
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist


--=20
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