To All:
Thanks to those who helped me get the RSSI sent over the serial port.
I am using the Telos B motes and doing some RSSI experiments. I am in
the process of modifying the serial forwarder some so that it will
convert the RSSI value I receive over the serial port to the actual
RSSI value. In the sflisten.c file, I have added the following code
to do this conversion before displaying it on the monitor:
const unsigned char *packet = read_sf_packet(fd, &len);
/*Perform 2's complement conversion and add offset (-45 dBm)*/
if (packet[10] < 128) //Positive Number
adj_rssi = packet[10];
if (packet[10] > 127) //Negative number
{
adj_rssi = -1*((packet[10] - 1)^(0xFF))-45;
}
if (!packet)
exit(0);
/*Display various information from the packet to monitor*/
printf("Node ID: ");
printf("%02x ", packet[12]);
printf("RAW RSSI: ");
printf("%02x ", packet[10]);
printf("Adjusted RSSI: ");
printf("%d ", adj_rssi);
putchar('\n');
fflush(stdout);
free((void *)packet);
The way I understand it, the raw RSSI is an 8-bit unsigned integer.
So, I have to do the two's complement conversion and add the offset.
Then I simply parse out what I want from the packet and print it
along with the converted RSSI to the screen. Does anyone see an
obvious flaw in my conversion or a more compact way to do the
conversion--aside from changing the if/if to and if/else. (I was
coding very late last night lol)
Many thanks again for the help.
Paul
*****************************************
Paul David Kavan
[EMAIL PROTECTED]
329 Walter Scott Engineering Center
University of Nebraska
402-472-2764
*****************************************
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