contiki/examples/sensinode/blink-hello.c
2012-03-23 14:41:07 +00:00

92 lines
3.2 KiB
C

/* This is a very simple hello_world program.
* It aims to demonstrate the co-existence of two processes:
* One of them prints a hello world message and the other blinks the LEDs
*
* It is largely based on hello_world in $(CONTIKI)/examples/sensinode
*
* Author: George Oikonomou <G.Oikonomou@lboro.ac.uk>
*/
#include "contiki.h"
#include "dev/leds.h"
#include <stdio.h> /* For printf() */
/*---------------------------------------------------------------------------*/
/* We declare the two processes */
PROCESS(hello_world_process, "Hello world process");
PROCESS(blink_process, "LED blink process");
/* We require the processes to be started automatically */
AUTOSTART_PROCESSES(&hello_world_process, &blink_process);
/*---------------------------------------------------------------------------*/
/* Implementation of the first process */
PROCESS_THREAD(hello_world_process, ev, data)
{
/* variables are declared static to ensure their values are maintained
between subsequent calls.
All the code between PROCESS_THREAD and PROCESS_BEGIN() runs each time
the process is invoked. */
static struct etimer timer;
static int count;
/* any process must start with this. */
PROCESS_BEGIN();
/* set the etimer module to generate an event in one second.
CLOCK_CONF_SECOND is #define as 128 */
etimer_set(&timer, CLOCK_CONF_SECOND * 4);
count = 0;
/* Don't declare variables after PROCESS_BEGIN.
* While it will compile fine with TARGET=native (gcc is happy),
* SDCC doesn't like it. Soon as you try TARGET=sensinode you will get:
* syntax error: token -> 'int' ;
* Try uncommenting the line below and observe the results */
/* int whoops = 0;
* whoops = 0; */
while (1)
{
/* wait here for an event to happen */
PROCESS_WAIT_EVENT();
/* This achieves the same
* PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_TIMER); */
/* if the event is the timer event as expected... */
if(ev == PROCESS_EVENT_TIMER)
{
/* do the process work */
printf("Sensor says no... #%d\r\n", count);
count ++;
/* reset the timer so it will generate an other event
* the exact same time after it expired (periodicity guaranteed) */
etimer_reset(&timer);
}
/* and loop */
}
/* any process must end with this, even if it is never reached. */
PROCESS_END();
}
/*---------------------------------------------------------------------------*/
/* Implementation of the second process */
PROCESS_THREAD(blink_process, ev, data)
{
static struct etimer timer;
PROCESS_BEGIN();
while (1)
{
/* we set the timer from here every time */
etimer_set(&timer, CLOCK_CONF_SECOND);
/* and wait until the event we receive is the one we're waiting for */
PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_TIMER);
printf("Blink... (state %0.2X).\r\n", leds_get());
/* update the LEDs */
leds_toggle(LEDS_GREEN);
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/