Sorry for the delay, but I was away for a few days ... and then got the flu...
On 23/12/15 14:59, Jorge Ramirez Ortiz wrote:
On 12/23/2015 03:44 AM, GianPiero Puccioni wrote:
On 23/12/15 00:45, Jorge Ramirez Ortiz wrote:
have you tried reading the Xenomai demo code or the analogy utilities?
http://git.xenomai.org/xenomai-3.git/tree/utils/analogy
Yes, of course, but the analogy utils are not written for realtime
what do you mean? do you see mode switches when you run them?
I havent executed them in a while but as far as I remember some of them were.
(and there
are some bits missing, for example insn_read does not set the range properly),
could you point me where?
I think it's where it calls a4l_sync_read and passes CHAN, that is only the
channel info but not the range. While the range is used when printing the
output, resulting in wrong values.
and the realtime examples are quite obscure for a beginner: only sparse comments
and no explanation on what's going on.
if you want a 101 example have a look at this control program
http://git.xenomai.org/xenomai-jro.git/tree/demo/posix/cobalt/gpiopwm.c?h=410c
it opens an rtdm driver that generates a PWM signal using a GPIO
http://git.xenomai.org/xenomai-jro.git/tree/kernel/drivers/gpiopwm/gpiopwm.c?h=410c
The control program spawns two threads one to set the PWM signal base
configuration and another one to change the duty cycle (either automatically or
via user control, optional vi command line)
The driver presents a rt path to change the duty cycle and start/stop the PWM
signal (so no mode switches, always running in primary mode) and a non-rt path
to set the config.
The config has to be in a non-rt path since the kernel framework to configure
the GPIO requires some non-rt linux services.
It doesnt get any simpler than that I believe.
Thanks, I'll check that.
GianPiero
--
GianPiero Puccioni |Istituto dei Sistemi Complessi-CNR
gianpiero.pucci...@isc.cnr.it |Via Madonna del Piano, 10
T:+39 0555226682 F:+39 0555226683|50019 Sesto F. (Firenze) ITALY
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