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<div class="moz-cite-prefix">Le 14/10/2014 19:51, Martin Peach a
écrit :<br>
</div>
<blockquote
cite="mid:CAN5xZ3ZRkVjnKZ_7ottgu2Vzk41TWf-1cUy2c_kSDZpbnmYD9g@mail.gmail.com"
type="cite">
<div dir="ltr">Oh sorry, I thought you were using an arduino.<br>
<br>
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<br>
I'm using an emulated arduino, it's called pcduino and it's the most
powerfull miniPC we can actually find.<br>
PureData is running so fine on it even through ssh there is no
latency like I've encountered on raspberry,<br>
and Multitrack USB soundcards runs greatly on it.<br>
<br>
<blockquote
cite="mid:CAN5xZ3ZRkVjnKZ_7ottgu2Vzk41TWf-1cUy2c_kSDZpbnmYD9g@mail.gmail.com"
type="cite">
<div dir="ltr">Martin<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Oct 14, 2014 at 1:16 PM, Colet
Patrice <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:colet.patrice@free.fr" target="_blank">colet.patrice@free.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>Le 14/10/2014 15:06, Martin Peach a écrit :<br>
</div>
<span class="">
<blockquote type="cite">
<div dir="ltr">
<div>Not sure why it segfaults, just want to say
that that method is really bad. Because of Pd's
control rate as well as the serial interface
latency, your timing will be really sketchy. The
way to do what you want is to implement the
ranging entirely on the arduino and send the
values back to Pd via [comport]. So a Pd [pulseIn]
object shoud simply send a request to the arduino
to start a pulse and return the time. It could be
implemented as an abstraction containing
[comport].<br>
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<br>
</span> I'm not using serial to read gpio state but
fopen() (may be fopen() is not fast enough), like in a
raspberry (but it's not on raspberry), I will try to do
this with python and use pdsend for retrieving value into
puredata.<br>
thank you for the advice.<br>
pc
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<div class="h5"><br>
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<div dir="ltr">Martin<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Oct 13, 2014 at
9:29 PM, Colet Patrice <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:colet.patrice@free.fr"
target="_blank">colet.patrice@free.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">Hello, I'm trying to
implement the pulseIn() function we can find
in arduino libraries into an external.<br>
<br>
I couldn't make it work because some part
doesn't seem to behave like I expect so I'm
wondering if it's caused by puredata process,<br>
so maybe someone in the list could enlight me
about that.<br>
<br>
The purpose of the external is about using an
ultrasound sensor connected on gpio that
require a microsecond timer for getting
distance like this:<br>
<br>
<br>
//here is a custom timer using a struct
provided by pcduino headers:<br>
#include core.h<br>
unsigned long pat_micros() {<br>
struct timeval tv;<br>
gettimeofday(&tv,NULL);<br>
return
tv.tv_sec*(uint64_t)1000000+tv.tv_usec;<br>
}<br>
<br>
//here is the custom pulseIn() function:<br>
unsigned long pat_pulseIn(t_pdpcduino *x, int
pin)<br>
{<br>
unsigned long timeout = 100000;<br>
unsigned long start = pat_micros();<br>
<br>
while( pdpcduino_gpio_read2 (x, pin) == 1
)<br>
if( pat_micros() - start > timeout
)<br>
return 0;<br>
<br>
// this is where I'm getting a segmentation
fault:<br>
<br>
while ( pdpcduino_gpio_read2 (x, pin) == 0
)<br>
if( pat_micros() - start > timeout
)<br>
return 0;<br>
<br>
//...<br>
unsigned long value = pat_micros();<br>
<br>
while( pdpcduino_gpio_read2 (x, pin) == 1
)<br>
if( pat_micros() - start > timeout
)<br>
return 0;<br>
<br>
return pat_micros() - value;<br>
<br>
}<br>
<br>
//...<br>
<br>
<br>
If I reduce the timeout number, segfault comes
randomly after this function has been
triggered, so I'm wondering if this method is
really appropriate,<br>
is there an exemple of external (containing
such while loops) I could get inspired from to
write this pulseIn() function?<br>
<br>
<br>
<br>
<br>
<br>
<br>
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