Re: [iPAQ] usleep

Paulo Marques wrote:

> If you're trying to control a robot, the best solution is to keep the
> real-time stuff on the microcontroller on the robot.
>
> The *normal* architecture would be to have a microcontroller read
> inputs (encoders, proximity sensors, touch sensors, etc., etc.) and
> drive outputs (motors, servos, lights, etc.). This microcontroller
> would communicate with the host application at a reasonable rate (25Hz
> ~ 100Hz) through the serial port.
>
> The application would process the data from the microcontroller and
> send new data for the microcontroller to update the outputs.

>
> It could then use a separate process with lower priority to display
> nice graphics and get input from the user on the touch device :)

That's exactly what I do !!!!!!! The IPAQ communicate with a master
microcontroler at about 200Hz using uart, and our master microcontroler
communicates with three other through SPI !!! But to have a high level
strategy, I need some good timings on the IPAQ ... For the process of
the data from the microcontrolers, I use signal handlers and thnigs like
that to avoid the even harder timings !!!! But we still need some good
timings because our four microcontrolers can't hande all the stuff (we
want to program a high level strategy !!!!) at 200 Hz !!!

But I've tried with nanosleep, should be better ... but I think I can
hardly go precisely under the 10ms precision of the OS (I suppose it is
10ms since it is so on x86 linux) ...

So I have another question : what linux/distro would you recommand me to
have RT Linux (on the IPAQ of maybe on x86 for other appz) ?

thx

Val
Received on Wed Apr 14 07:57:12 2004