// Set the channel fast and discard the first wrong readings
void my_set_channel(int ch)
{
  int k, temp;
  SPI_SETCHANNEL_SUPERFAST(357+((ch-11)*5)); // Approx. 292 us
  // Discard first 16 bad readings
  CC2420_SPI_ENABLE();
  for (k=0; k<=16; k++) {
    MY_FASTSPI_GETRSSI(temp);
  }
  clock_delay(1);
  CC2420_SPI_DISABLE();
}
Ejemplo n.º 2
0
PROCESS_THREAD(scanning, ev, data)
{
 PROCESS_BEGIN();
 
 // Initial operations
 leds_off(LEDS_ALL);
 watchdog_stop(); 
 
 // Avoiding wrong RSSI readings
 unsigned temp;
 CC2420_READ_REG(CC2420_AGCTST1, temp);
 CC2420_WRITE_REG(CC2420_AGCTST1, (temp + (1 << 8) + (1 << 13))); 
 
 // Selecting the channel	
 SPI_SETCHANNEL_SUPERFAST(357+((CHANNEL-11)*5));
 
 // Avoiding the initial wrong readings by discarding the wrong readings
 CC2420_SPI_ENABLE();
 unsigned long k=0;
 for (k=0; k<=15; k++) {MY_FASTSPI_GETRSSI(temp);}
 CC2420_SPI_DISABLE(); 
 
 static struct etimer et;
 while(1){
	 	 
	 #if VERBOSE
	 printf("#START (dBm: occurrencies)\n");
	 #endif
	 
	 // Resetting everything
	 for(k=0;k<BUFFER_SIZE;k++){	
		buffer0[k] = 0;
	 }
	 
	 dint();				// Disable interrupts
	 boost_cpu(); 			// Temporarily boost CPU speed
	 CC2420_SPI_ENABLE(); 	// Enable SPI
	
	 // Actual scanning 
	 static signed char rssi;
	 for(k=0; k<MAX_VALUE; k++){		
		MY_FASTSPI_GETRSSI(rssi);	
		buffer0[rssi+55]++;
	 }	
 
	 CC2420_SPI_DISABLE();	// Disable SPI
	 restore_cpu();			// Restore CPU speed
	 eint(); 				// Re-enable interrupts
 
	 // Printing the stored values in compressed form 
	 unsigned long sum_cca = 0;
	 unsigned long max = 0, max_value = 0;
	 for(temp=0; temp<BUFFER_SIZE; temp++) {	
		sum_cca += (temp * buffer0[temp]);
		if(buffer0[temp] > max){
			max = buffer0[temp];
			max_value = temp;
		}		
	 }
	 
	 // Printing the results of the CCA
	 float f_cca = (((float) sum_cca*1.0000) / MAX_VALUE)-100.0000;		
	 #if VERBOSE
		printf("Average noise: %ld.%04u\nStatistic Mode noise: %ld\n", (long) f_cca, (unsigned)((f_cca-floor(f_cca))*10000), max_value-100);
	 #else
		printf("%ld.%04u\n", (long) f_cca, (unsigned)((f_cca-floor(f_cca))*10000));
	 #endif
	 
	 #if VERBOSE
		printf("#END\n");
	 #endif
	 
	 // Waiting for timer
	 etimer_set(&et, PERIOD_TIME);
	 PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));	
 
 }
 
 PROCESS_WAIT_EVENT();
 
 PROCESS_END();
}
Ejemplo n.º 3
0
PROCESS_THREAD(scanning, ev, data)
{
    PROCESS_BEGIN();

// Initial operations
    leds_off(LEDS_ALL);
    watchdog_stop();

// Avoiding wrong RSSI readings
    unsigned temp;
    CC2420_READ_REG(CC2420_AGCTST1, temp);
    CC2420_WRITE_REG(CC2420_AGCTST1, (temp + (1 << 8) + (1 << 13)));

// Selecting the channel
    SPI_SETCHANNEL_SUPERFAST(357+((CHANNEL-11)*5));

// Avoiding the initial wrong readings by discarding the wrong readings
    CC2420_SPI_ENABLE();
    int k=0;
    for (k=0; k<=15; k++) {
        MY_FASTSPI_GETRSSI(temp);
    }
    CC2420_SPI_DISABLE();

    static struct etimer et;
    while(1) {

        // Resetting everything
        for(k=0; k<(BUFFER_SIZE/2); k++) {
            buffer1[k] = 0;
            buffer0[k] = 0;
        }

        printf("#START [dBm: occurrencies]\n");

        dint();				// Disable interrupts
        boost_cpu(); 			// Temporarily boost CPU speed
        CC2420_SPI_ENABLE(); 	// Enable SPI

        // Actual scanning
        static signed char rssi;
        int current = 0;
        int previous = 0;
        int cnt = 1;
        for(k=0; k<(BUFFER_SIZE/2);) {
            // Sample the RSSI fast
            MY_FASTSPI_GETRSSI(rssi);
            current = rssi + 55;
            if((current == previous)&&(cnt<255)) {
                cnt++;
            }
            else {
                buffer0[k] = previous;
                buffer1[k++] = cnt;
                cnt = 1;
                previous = current;
            }
        }

        CC2420_SPI_DISABLE();	// Disable SPI
        restore_cpu();			// Restore CPU speed
        eint(); 				// Re-enable interrupts

        // Printing the stored values in compressed form
        for(temp=0; temp<(BUFFER_SIZE/2); temp++) {
            printf("%d: %d\n",buffer0[temp] - 100, buffer1[temp]);
            clock_delay(30000);
        }

        printf("#END\n");

        // Waiting for timer
        etimer_set(&et, PERIOD_TIME);
        PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));

    }

    PROCESS_WAIT_EVENT();

    PROCESS_END();
}