osd-contiki/examples/sensinode/energy-scan/energy-scan.c

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2012-03-05 17:28:06 +01:00
/*
* Copyright (c) 2010, Loughborough University - Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*/
/**
* \file
* Minimalistic channel energy detection.
*
* \author
* George Oikonomou - <oikonomou@users.sourceforge.net>
*/
#include "contiki.h"
#include "cc2430_sfr.h"
#include "sensinode-debug.h"
#include "dev/cc2430_rf.h"
#include <stdio.h>
static uint8_t channel;
static int8_t j;
static int8_t cmax;
static int8_t rssi;
static struct etimer et;
static rtimer_clock_t t0;
#define RSSI_BASE -50
#define RSSI_SAMPLES 30
#define SAMPLE_INTERVAL (CLOCK_SECOND)
#define CHANNEL_MIN 11
#define CHANNEL_MAX 26
/* ToDo: Do this in infinite RX. Take more samples */
/*---------------------------------------------------------------------------*/
PROCESS(energy_scan, "Energy Scanner");
AUTOSTART_PROCESSES(&energy_scan);
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(energy_scan, ev, data)
{
PROCESS_BEGIN();
printf("Energy Scanner\n");
printf("CCA Threshold: %d\n", (int8_t)RSSIH);
printf("Channel scan range: [%u , %u]\n", CHANNEL_MIN, CHANNEL_MAX);
printf("%u samples per channel, interval %u ticks\n",
RSSI_SAMPLES, SAMPLE_INTERVAL);
channel = CHANNEL_MIN;
while(1) {
cmax = RSSI_BASE;
cc2430_rf_channel_set(channel);
clock_delay(200);
for(j = 0; j < RSSI_SAMPLES; j++) {
t0 = RTIMER_NOW();
rssi = RSSIL;
if(rssi > cmax) {
cmax = rssi;
}
while(RTIMER_CLOCK_LT(RTIMER_NOW(), t0 + 25));
}
printf("%u [%3d]: ", channel, cmax);
for(j = RSSI_BASE; j <= cmax; j++) {
printf("#");
}
printf("\n");
if(channel == CHANNEL_MAX) {
printf("===============\n");
channel = CHANNEL_MIN;
} else {
channel++;
}
etimer_set(&et, SAMPLE_INTERVAL);
PROCESS_YIELD();
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/