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 Robotics / RCX / 1726
1725  |  1727
Subject: 
HOWTO Demo.c
Newsgroups: 
lugnet.robotics.rcx
Date: 
Tue, 2 Jul 2002 13:39:19 GMT
Viewed: 
2826 times
  
I was able to fix the previous problem regarding the light sensor

Thank u Joseph Woolley for your reply.

I have another one

In the legOS Howto their is a demo code demo.c which has some
task switching examples

I am having trouble with the following piece of code

int task_swapper()
{
wait_event(&button_press_wakeup,BUTTON_VIEW); /*wait for PROGRAM button*/
wait_event(&button_release_wakeup,BUTTON_VIEW);/*wait for release*/

pid2=execi(&motor_driver, 0, NULL, 2, DEFAULT_STACK_SIZE);/*start motor
example*/

wait_event(&button_press_wakeup,BUTTON_VIEW); /*wait for PROGRAM button*/
wait_event(&button_release_wakeup,BUTTON_VIEW); /*wait for release*/

kill(pid2); /*kill motor example*/

motor_a_speed(off);
motor_c_speed(off);

pid3=execi(&light_sensor, 0, NULL, 3, DEFAULT_STACK_SIZE);/*start light
example*/

wait_event(&button_press_wakeup,BUTTON_VIEW); /*wait for PROGRAM button*/
wait_event(&button_release_wakeup,BUTTON_VIEW);/*wait for release*/

kill(pid3); /*kill light example*/

ds_passive(&SENSOR_2); /* turn off light sensor LED (passive mode again) */

pid4=execi(&touch_sensor, 0, NULL, 4, DEFAULT_STACK_SIZE);/*start touch
example*/

wait_event(&button_press_wakeup,BUTTON_VIEW); /*wait for PROGRAM button*/
wait_event(&button_release_wakeup,BUTTON_VIEW);/*wait for release*/

kill(pid4); /*kill touch example*/

lcd_clear();
sleep(1);
cputs("reset");
sleep(3);
return 0;
}

after the program is started with the run button and the view button is pressed
the first task (motor example pid2) starts and it works .

but if I press the view button a second time the RCX hangs.
Display gets stuck to what is already on it , no buttons work any more
including on/off.

So I have to take out the batteries and when I put them back I have to re
install the firmaware as well.

I have tried changing the button to BUTTON_PROGRAM but get the same result
changing it to BUTTON_RUN does not work any way because if run pressed once the
program is started the program stops.

I also tried using a touch sensor along with a wakeup function to switch
between task but the same behaviour happens.( I have tried it quite a lot of
times)

I did a search on the mailing list too there was a post which mentioned that
the the HOWTO is old and in the newer legOS "the buttons have been incorporated
in the OS and perhaps there isn't a way to decuple them from the OS".

Could this be the reason or does somone have an idea.

Many Thanks

Shehryar



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