osd-contiki/examples/sensinode/event-post/event-post.c

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2012-03-05 17:28:06 +01:00
/* This file demonstrates the interaction between two processes via events.
*
* - "Sensor process": Throws an event periodically. This can be for example a
* sensor value.
* - "Print process" : Waits for events from "Sensor" and prints a message when
* an event occurs (e.g. prints the sensor value)
*
* This example is derived from the contiki code examples for the WSN430
* (SensTools - Inria: http://senstools.gforge.inria.fr/)
*
* Author: George Oikonomou <G.Oikonomou@lboro.ac.uk>
*/
#include "contiki.h"
//#include "dev/leds.h"
#include <limits.h>
#include <stdio.h> /* For printf() */
#include "event-post.h"
/* This is our event type */
static process_event_t event_data_ready;
/*---------------------------------------------------------------------------*/
/* Declare the two processes here */
PROCESS(sensor_process, "Sensor process");
PROCESS(print_process, "Print process");
/* Tell Contiki that we want them to start automatically */
AUTOSTART_PROCESSES(&sensor_process, &print_process);
/*---------------------------------------------------------------------------*/
/* Implementation "Sensor Process" */
PROCESS_THREAD(sensor_process, ev, data)
{
/* static variables to preserve values across consecutive calls of this
* process. */
/* Set an etimer */
static struct etimer timer;
/* And the 'sensor' monitoring variable */
static struct event_struct es;
PROCESS_BEGIN();
/* Set some near-the-limit initial values */
/* signed primitives */
es.s_val = SHRT_MAX-2;
es.i_val = INT_MAX-2;
es.l_val = LONG_MAX-2;
/* sizeof(long long) == sizeof(long) on sensinodes - see other examples*/
es.ll_val = LONG_MAX-2;
/* and some typedef-ed unsigned variables */
es.u8_val = UCHAR_MAX-2;
es.u16_val = USHRT_MAX-2;
es.u32_val = ULONG_MAX-2;
/* allocate the required event */
event_data_ready = process_alloc_event();
/* process_event_t is actually a u_char. What did the OS allocate for us? */
printf("Contiki allocated event ID %d.\r\n", event_data_ready);
/* Set a timer here. We will generate an event every times this timer expires
* etimer_set accepts clock ticks as its 2nd argument.
* CLOCK_CONF_SECOND is the number of ticks per second.
* This CLOCK_CONF_SECOND * N = N seconds */
etimer_set(&timer, CLOCK_CONF_SECOND * 2);
while (1)
{
printf("Sensor process: Wait for timer event...\r\n");
/* Wait on our timer */
PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_TIMER);
/* blip */
/* leds_toggle(LEDS_BLUE); */
/* Set the 'sensor' value before throwing the event */
printf("Sensor Process: Incrementing values...\r\n");
es.s_val++;
es.i_val++;
es.l_val++;
es.ll_val++;
es.u8_val++;
es.u16_val++;
es.u32_val++;
/* Post our event.
* N.B. es is declared static.
* Try passing a volatile variable and observe the results... */
printf("Sensor Process: Generating 'Data Ready' event.\r\n");
process_post(&print_process, event_data_ready, &es);
/* reset the timer so we can wait on it again */
etimer_reset(&timer);
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/
/* Implementation of "Print Process" */
PROCESS_THREAD(print_process, ev, data)
{
struct event_struct * sd;
PROCESS_BEGIN();
while (1)
{
/* Stop here and wait until "event_data_ready" occurs */
PROCESS_WAIT_EVENT_UNTIL(ev == event_data_ready);
/* When the event occurs, the incoming data will be stored in
* process_data_t data (careful, this is void *)
*
* Print away...
* es is volatile, we need to set it = data again and dereference it. */
sd = data;
printf("Print Process - Data Ready:\r\n");
printf(" s: %d\r\n", sd->s_val);
printf(" i: %d\r\n", sd->i_val);
printf(" l: %ld\r\n", sd->l_val);
printf(" ll: %lld\r\n", sd->ll_val);
printf(" u8: %u\r\n", sd->u8_val);
printf(" u16: %u\r\n", sd->u16_val);
printf(" u32: %lu\r\n", sd->u32_val);
/* aaaaand back to waiting for the next event */
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/