Samir,
Where did you conduct your experiments?
Due to the presence of multipath effects indoor reading may not fall off with
distance.
You can get a close to ideal environment by putting motes on to the ground in
some wide open space (parking lot, roof, etc.).
Due to small-scale effects signal strength readings will oscillate even when
you are at the same distance from the transmitter.
To extract large-scale values (these values fall off with the distance) you
could average your readings over time at the same distance.
I am using 0x96 sequence in the packet. I forgot to mention it, sorry about
that.
Regards,
Vladimir.
Samir Goel wrote:
> hello Vladimir,
> Thanks for sending the files. When I tested it out, I did get reduction
> in signal strength as I moved away from the source. But the reduction was
> very small --- the reading varied from between 325 (closest) and 290
> (farthest). The readings showed significant oscillations (width of the
> oscillations was at times as large as 10 even when I was stationary). Is
> this what you observed or am I doing something wrong ? Please let me know.
>
> In his e-mail, Alec Woo suggested that I put a couple of 0x96,0xca bytes
> in the packet before transmitting. Are you following this approach ?
>
> I would appreciate any comments that you might have.
>
> Regards,
>
> Samir Goel
>
> ----- Original Message -----
> From: "Vladimir Bychkovskiy" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
> Sent: Monday, April 30, 2001 2:59 PM
> Subject: Re: [tinyos-users@mm] Extracting radio signal strength
>
> > I have been stuggling with the signal strength for a while now. Here are
> the
> > two componets that I am currently using, both of them are modifications
> of
> > the components that Alec Woo had sent to me.
> >
> > Let me know if this works for you.
> >
> > Vlad.
> >
> > [EMAIL PROTECTED] wrote:
> >
> > > By the way, Samir is not the only one having this problem. I've been
> > > trying to do the same thing for some time now, and have not had any
> > > success. I've located the character in the packet which is supposed to
> > > represent signal strength, but it always reads 00. If you find an
> answer
> > > Samir, I would appriciate hearing about it.
> > >
> > > "Samir Goel" <[EMAIL PROTECTED]> (Mailed by:
> > > [EMAIL PROTECTED])
> > > 04/29/2001 07:25 PM AST
> > > Please respond to "Samir Goel" <[EMAIL PROTECTED]>
> > >
> > > To: <[EMAIL PROTECTED]>
> > > cc: <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>
> > > Subject: Re: [tinyos-users@mm] Extracting radio signal strength
> > >
> > > hello All,
> > > I was able to get the code to compile (a bug from my own doing). But
> > > when I tested it out, I didn't observe any changes in signal strength
> > > correlated with distance. I would really appreciate if someone can help
> me
> > > out or point me in the right direction.
> > >
> > > Regards,
> > >
> > > Samir Goel
> > > [EMAIL PROTECTED]
> >
>
> ---------------------------------------------------------------------------
> -----
>
> > /* tab:4
> > *
> > *
> > * "Copyright (c) 2000 and The Regents of the University
> > * of California. All rights reserved.
> > *
> > * Permission to use, copy, modify, and distribute this software and its
> > * documentation for any purpose, without fee, and without written
> agreement is
> > * hereby granted, provided that the above copyright notice and the
> following
> > * two paragraphs appear in all copies of this software.
> > *
> > * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
> FOR
> > * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
> ARISING OUT
> > * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE
> UNIVERSITY OF
> > * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> > *
> > * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
> > * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
> MERCHANTABILITY
> > * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER
> IS
> > * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO
> OBLIGATION TO
> > * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
> MODIFICATIONS."
> > *
> > * Authors: Jason Hill
> > *
> > *
> > */
> >
> > #include "tos.h"
> > //#define FULLPC_DEBUG 1
> > #include "PACKETOBJ_SIGNAL.h"
> >
> >
> > #define TOS_FRAME_TYPE PACKET_obj_frame
> > TOS_FRAME_BEGIN(PACKET_obj_frame) {
> >
> > char state;
> > char count;
> > TOS_Msg buffer;
> > char* rec_ptr;
> > char* send_ptr;
> > //int strength;
> > int ss_sum;
> > int ss_cnt;
> > }
> > TOS_FRAME_END(PACKET_obj_frame);
> >
> >
> >
> > char TOS_COMMAND(PACKET_TX_PACKET)(TOS_MsgPtr msg){
> > if(VAR(state) == 0){
> > VAR(send_ptr) = (char*)msg;
> > VAR(state) = 1;
> > VAR(count) = 1;
> > if(TOS_CALL_COMMAND(PACKET_SUB_TX_BYTES)(VAR(send_ptr)[0])){
> > return 1;
> > }else{
> > VAR(state) = 0;
> > VAR(count) = 0;
> > return 0;
> > }
> > }else{
> > return 0;
> > }
> > }
> >
> > void TOS_COMMAND(PACKET_POWER)(char mode){
> > //do this later;
> > ;
> > }
> >
> >
> > char TOS_COMMAND(PACKET_INIT)(){
> > TOS_CALL_COMMAND(PACKET_SUB_INIT)();
> > VAR(rec_ptr) = (char*)&VAR(buffer);
> > VAR(state) = 0;
> > #ifdef FULLPC
> > printf("Packet handler initialized.\n");
> > #endif
> > return 1;
> > }
> >
> >
> > char TOS_EVENT(PACKET_RX_BYTE_READY)(char data, char error, int
> strength){
> > #ifdef FULLPC_DEBUG
> > printf("PACKET: byte arrived: %x, STATE: %d, COUNT: %d\n", data,
> VAR(state), VAR(count));
> > #endif
> > if(error){
> > VAR(state) = 0;
> > return 0;
> > }
> > if(VAR(state) == 0){
> > VAR(state) = 5;
> > VAR(count) = 1;
> > VAR(rec_ptr)[0] = data;
> > //VAR(strength) = strength;
> > VAR(ss_sum)=strength;
> > VAR(ss_cnt)=1;
> > }else if(VAR(state) == 5){
> > VAR(rec_ptr)[(int)VAR(count)] = data;
> > VAR(count)++;
> > if (strength != 0){
> > /*
> > VAR(strength) += strength;
> > VAR(strength) >>= 1;
> > */
> > VAR(ss_sum)+=strength;
> > VAR(ss_cnt)++;
> > }
> > if(VAR(count) == sizeof(TOS_Msg) -
> sizeof(((TOS_MsgPtr)(VAR(rec_ptr)))->strength)){
> > TOS_MsgPtr tmp;
> > printf("got packet\n");
> > VAR(state) = 0;
> > ((TOS_MsgPtr)(VAR(rec_ptr)))->strength=(VAR(ss_sum)/VAR(ss_cnt));
> //VAR(strength);
> > tmp =
> TOS_SIGNAL_EVENT(PACKET_RX_PACKET_DONE)((TOS_Msg*)VAR(rec_ptr));
> > if(tmp != 0) VAR(rec_ptr) = (char*)tmp;
> > return 0;
> > }
> > }
> > return 1;
> > }
> >
> >
> > char TOS_EVENT(PACKET_TX_BYTE_READY)(char success){
> > char i;
> > if(success == 0){
> > printf("TX_packet failed, TX_byte_failed");
> > TOS_SIGNAL_EVENT(PACKET_TX_PACKET_DONE)(0);
> > VAR(state) = 0;
> > VAR(count) = 0;
> > }
> > if(VAR(state) == 1){
> > if(VAR(count) < sizeof(TOS_Msg) - sizeof(
> ((TOS_MsgPtr)(VAR(rec_ptr)))->strength)){
> > #ifdef FULLPC_DEBUG
> > printf("PACKET: byte sent: %x, STATE: %d, COUNT: %d\n",
> VAR(send_ptr)[(int)VAR(count)], VAR(state), VAR(count));
> > #endif
> >
> TOS_CALL_COMMAND(PACKET_SUB_TX_BYTES)(VAR(send_ptr)[(int)VAR(count)]);
> > VAR(count)++;
> > }else if(VAR(count) == sizeof(TOS_Msg) - sizeof(
> ((TOS_MsgPtr)(VAR(rec_ptr)))->strength)){
> > VAR(count)++;
> > return 0;
> > }else{
> > VAR(state) = 0;
> > VAR(count) = 0;
> > TOS_SIGNAL_EVENT(PACKET_TX_PACKET_DONE)((TOS_MsgPtr)VAR(send_ptr));
> > return 0;
> > }
> > }
> > return 1;
> > }
> > char TOS_EVENT(PACKET_BYTE_TX_DONE)(){
> > return 1;
> > }
> >
>
> ---------------------------------------------------------------------------
> -----
>
> > /* tab:4
> > *
> > *
> > * "Copyright (c) 2000 and The Regents of the University
> > * of California. All rights reserved.
> > *
> > * Permission to use, copy, modify, and distribute this software and its
> > * documentation for any purpose, without fee, and without written
> agreement is
> > * hereby granted, provided that the above copyright notice and the
> following
> > * two paragraphs appear in all copies of this software.
> > *
> > * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
> FOR
> > * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
> ARISING OUT
> > * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE
> UNIVERSITY OF
> > * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> > *
> > * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
> > * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
> MERCHANTABILITY
> > * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER
> IS
> > * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO
> OBLIGATION TO
> > * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
> MODIFICATIONS."
> > *
> > * Authors: Jason Hill
> > *
> > *
> > */
> >
> >
> > #include "tos.h"
> > #include "SEC_DED_RADIO_BYTE_SIGNAL.h"
> >
> >
> > /* list of states:
> > *
> > * 0 -- wating in idle mode, searching for start symbol
> > * 1 -- starting a transmission, 0 bytes encoded.
> > * 2 -- 1 byte encoded
> > * 3 -- 1 byte encoded, 1 byte waiting to be encoded
> > * 4 -- 2 bytes encoded
> > * 5 -- start symbol received waiting for first bit
> > * 6 -- clocking in bits
> > *
> > * 10 -- waiting to listen for idle channel
> > */
> >
> >
> >
> > #define TOS_FRAME_TYPE bitread_frame
> > TOS_FRAME_BEGIN(radio_frame) {
> > char primary[3];
> > char secondary[3];
> > char state;
> > char count;
> > char last_bit;
> > char waiting;
> > int strength;
> > char s_count;
> > int led_state;
> >
> > }
> > TOS_FRAME_END(radio_frame);
> >
> > TOS_TASK(radio_encode_thread)
> > {
> > //encode byte and store it into buffer.
> > encodeData();
> > //if this is the start of a transmisison, encode the start symbol.
> > if(VAR(state) == 1){
> >
> > //VAR(primary)[1] = 0x26; //start frame 0x00100110
> > //VAR(primary)[2] = 0xb5; //start frame 0x10110101
> >
> > //VAR(primary)[0] = 0x1; //start frame 0x1
> > //VAR(primary)[1] = 0x35; //start frame 0x00110101
> > //VAR(primary)[2] = 0x15; //start frame 0xXXX10101
> > //VAR(count) = 3;
> >
> > VAR(primary)[0] = 0x2; //start frame 0x10
> > VAR(primary)[1] = 0x6b; //start frame 0x01101011
> > VAR(primary)[2] = 0x05; //start frame 0xXXXX0101
> > VAR(count) = 4;
> >
> >
> > VAR(state) = 4;//there are now 2 bytes encoded.
> > }else{
> > VAR(state) = 4;//there are now 2 bytes encoded.
> > }
> >
> > #ifdef FULLPC_DEBUG
> > printf("radio_encode_thread running: %x, %x\n", VAR(secondary[1]),
> VAR(secondary[2]));
> > #endif
> > }
> >
> > TOS_TASK(radio_decode_thread)
> > {
> > int strength;
> > #ifdef FULLPC_DEBUG
> > printf("radio_decode_thread running: %x, %x\n", VAR(secondary[1]),
> VAR(secondary[2]));
> > #endif
> > //check the signal strength;
> >
> > strength = VAR(strength) >> 2;
> > VAR(strength) = 0;
> > VAR(s_count) = 0;
> > printf("byte strength %x\n", strength);
> >
> > //decode the byte that has been recieved.
> > if(!TOS_SIGNAL_EVENT(RADIO_BYTE_RX_BYTE_READY)(decodeData(), 0,
> strength)){
> > //if the event returns false, then stop receiving, go to search for the
> > //start symbol at the high sampling rate.
> > VAR(state) = 0;
> > TOS_CALL_COMMAND(RADIO_SUB_SET_BIT_RATE)(0);
> > }
> > }
> >
> >
> > char TOS_COMMAND(RADIO_BYTE_INIT)(){
> > VAR(state) = 0;
> > TOS_CALL_COMMAND(RADIO_SUB_INIT)();
> >
> > // Added by BVL
> > TOS_CALL_COMMAND(SIGNAL_ADC_INIT)();
> > // -----
> > #ifdef FULLPC
> > printf("Radio Byte handler initialized.\n");
> > #endif
> > return 1;
> > }
> >
> > char TOS_COMMAND(RADIO_BYTE_TX_BYTES)(char data){
> > #ifdef FULLPC_DEBUG
> > printf("TX_bytes: state=%x, data=%x\n", VAR(state), data);
> > #endif
> > if(VAR(state) == 0){
> > //if currently in idle mode, then switch over to transmit mode
> > //and set state to waiting to transmit first byte.
> > VAR(secondary[0]) = data;
> > VAR(state) = 10;
> >
> > #ifdef FULLPC
> > VAR(waiting) = 9;
> > TOS_SIGNAL_EVENT(RADIO_BYTE_RX_BIT_EVENT)(0);
> > #endif
> >
> > return 1;
> > }else if(VAR(state) == 2){
> > //if in the middle of a transmission and one byte is encoded
> > //go to the one byte encoded and one byte in the encode buffer.
> > VAR(state) = 3;
> > VAR(secondary[0]) = data;
> > //schedule the encode task.
> > TOS_POST_TASK(radio_encode_thread);
> > return 1;
> > }else if(VAR(state) == 4){
> > return 0;
> > }
> > return 0;
> > }
> >
> > //mode 1 = active;
> > //mode 0 = sleep;
> >
> > char TOS_COMMAND(RADIO_BYTE_PWR)(char mode){
> > if(mode == 0){
> > //if low power mode, tell lower components
> > VAR(state) = 0;
> > TOS_CALL_COMMAND(RADIO_SUB_PWR)(0);
> > }else{
> > //set the RMF component into "search for start symbol" mode.
> > TOS_CALL_COMMAND(RADIO_SUB_PWR)(1);
> > TOS_CALL_COMMAND(RADIO_SUB_RX_MODE)();
> > TOS_CALL_COMMAND(RADIO_SUB_SET_BIT_RATE)(0);
> > VAR(state) = 0;
> > VAR(count) = 0;
> > VAR(last_bit) = 0xff;
> > VAR(waiting) = 0;
> > }
> > return 1;
> > }
> >
> >
> > char TOS_EVENT(RADIO_BYTE_TX_BIT_EVENT)(){
> > #ifdef FULLPC_DEBUG
> > printf("radio tx bit event %d\n", VAR(primary)[2] & 0x1);
> > #endif
> > //if we're not it a transmit state, return false.
> > if(VAR(state) != 2 && VAR(state) != 3 && VAR(state) != 4) return 0;
> > //send the next bit that we have stored.
> > TOS_CALL_COMMAND(RADIO_SUB_TX_BIT)(VAR(primary)[2] & 0x01);
> > //right shift the buffer.
> > VAR(primary)[2] = VAR(primary)[2] >> 1;
> > //increment our bytes sent count.
> > VAR(count) ++;
> > if(VAR(count) == 8){
> > //once 8 have gone out, get ready to send out the nibble.
> > VAR(primary)[2] = VAR(primary)[1];
> > }else if(VAR(count) == 16){
> > VAR(primary)[2] = VAR(primary)[0];
> > }else if(VAR(count) == 18){
> > if(VAR(state) == 4){
> > //if another byte is ready, then shift the
> > //data over to first and second.
> > VAR(primary)[0] = VAR(secondary)[0];
> > VAR(primary)[1] = VAR(secondary)[1];
> > VAR(primary)[2] = VAR(secondary)[2];
> >
> > VAR(count) = 0;
> > VAR(state) = 2;//now only one byte is bufferred.
> > TOS_SIGNAL_EVENT(RADIO_BYTE_TX_BYTE_READY)(1);//fire the byte
> transmitted event.
> > }else{
> > //if there are no bytes bufferred, go back to idle.
> > VAR(state) = 0;
> > TOS_SIGNAL_EVENT(RADIO_BYTE_TX_BYTE_READY)(1);
> > TOS_SIGNAL_EVENT(RADIO_BYTE_TX_DONE)();
> > TOS_CALL_COMMAND(RADIO_SUB_RX_MODE)();
> > TOS_CALL_COMMAND(RADIO_SUB_SET_BIT_RATE)(0);
> > }
> > }
> > return 1;
> > }
> >
> > char TOS_EVENT(RADIO_BYTE_RX_BIT_EVENT)(char data){
> > #ifdef FULLPC
> > //because the FULLPC version doesn't do 2x sampling, we fake it out
> with
> > //this.
> > VAR(last_bit) = data;
> > #ifdef FULLPC_DEBUG
> > printf("RX %d\n", data);
> > #endif
> > #endif
> > if(VAR(state) == 0){
> > //if we are in the idle state, the check if the bit read
> > //matches the last bit.
> > if(VAR(last_bit) != data){
> > VAR(last_bit) = data;
> > return 1;
> > }
> > //if so, set last bit to invalid,
> > VAR(last_bit) = 0xff;
> > //right shift previously read data.
> > VAR(primary)[2] >>= 1;
> > //mask out upper bit
> > VAR(primary)[2] &= 0x7f;
> > //if lowest bit of first is one, store it in second
> > if(VAR(primary)[1] & 0x1) VAR(primary)[2] = VAR(primary)[2] | 0x80;
> > //don't forget that the start symbol is only 9 bits long.
> > VAR(primary)[1] = data & 0x1;
> > #ifdef FULLPC_DEBUG
> > printf("checking for start symbol: %x, %x\n", VAR(primary)[1] & 0xff,
> > VAR(primary)[2] & 0xff);
> > #endif
> > //if you now have the start symbol, go to the waiting for first bit
> state.
> > if(VAR(primary)[1] == (char)0x1 && VAR(primary)[2] == (char)0x35){
> > VAR(state) = 5;
> > VAR(count) = 0;
> > //set bit rate so next sample falls in middle of next
> > //transmitted bit.
> > TOS_CALL_COMMAND(RADIO_SUB_SET_BIT_RATE)(1);
> > }
> >
> > }else if(VAR(state) == 5){
> > //just read first bit.
> > //set bit rate to match TX rate.
> > TOS_CALL_COMMAND(RADIO_SUB_SET_BIT_RATE)(2);
> > VAR(state) = 6;
> > VAR(count) = 1;
> > //store it.
> > if(data){
> > VAR(primary)[1] = 0x80;
> >
> > }else{
> > VAR(primary)[1] = 0;
> > }
> > }else if(VAR(state) == 6){
> > //clock in bit.
> > VAR(count)++;
> > VAR(primary)[1] >>= 1;
> > VAR(primary)[1] &= 0x7f;
> > if(data){
> > VAR(primary)[1] |= 0x80;
> > TOS_CALL_COMMAND(SIGNAL_ADC_GET_DATA)(0);
> > }
> > if(VAR(count) == 8){
> > VAR(secondary[2]) = VAR(primary[1]);
> > }else if(VAR(count) == 16){
> > VAR(count)++;
> > //sore the encoded data into a buffer.
> > VAR(secondary)[1] = VAR(primary)[1];
> > VAR(state) = 7;
> > //scheduled the decode task.
> > //TOS_POST_TASK(radio_decode_thread);
> > }
> > }else if(VAR(state) == 7){
> > VAR(secondary)[0] = data;
> > VAR(state) = 8;
> > }else if(VAR(state) == 8){
> > //throw away the higest bit.
> > VAR(state) = 5;
> > //scheduled the decode task.
> > TOS_POST_TASK(radio_decode_thread);
> > #ifdef FULLPC_DEBUG
> > printf("entire byte received: %x, %x\n", VAR(secondary)[1],
> VAR(secondary)[2]);
> > #endif
> > }else if(VAR(state) == 10){
> > //waiting for channle to be idle.
> > if(data){
> > //if we just read activity, then reset the waiting counter.
> > VAR(waiting) = 0;
> > }else{
> > VAR(waiting) ++;
> > //if we've not heard anything for 8 samples then...
> > if(VAR(waiting) > 8){
> > //go to the transmitting state.
> > VAR(state) = 1;
> > VAR(waiting) = 0;
> > //schedule task to start transfer, set TX_mode, and set bit rate
> > TOS_CALL_COMMAND(RADIO_SUB_TX_MODE)();
> > TOS_CALL_COMMAND(RADIO_SUB_SET_BIT_RATE)(2);
> > TOS_POST_TASK(radio_encode_thread);
> > }
> > }
> > }
> > return 1;
> > }
> >
> >
> >
> > void encodeData(){
> > char ret_high = 0;
> > char ret_low = 0;
> > char ret_mid = 0;
> > char val = VAR(secondary[0]);
> > if((val & 0x1) != 0) {
> > ret_high ^=0;
> > ret_mid ^=0x0;
> > ret_low ^=0x77;
> > }
> > if((val & 0x2) != 0) {
> > ret_high ^=0;
> > ret_mid ^=0x1;
> > ret_low ^=0x34;
> > }
> > if((val & 0x4) != 0) {
> > ret_high ^=0;
> > ret_mid ^=0x2;
> > ret_low ^=0x32;
> > }
> > if((val & 0x8) != 0) {
> > ret_high ^=0;
> > ret_mid ^=0x8;
> > ret_low ^=0x31;
> > }
> > if((val & 0x10) != 0) {
> > ret_high ^=0;
> > ret_mid ^=0x10;
> > ret_low ^=0x26;
> > }
> > if((val & 0x20) != 0) {
> > ret_high ^=0;
> > ret_mid ^=0x60;
> > ret_low ^=0x25;
> > }
> > if((val & 0x40) != 0) {
> > ret_high ^=0;
> > ret_mid ^=0x80;
> > ret_low ^=0x13;
> > }
> > if((val & 0x80) != 0) {
> > ret_high ^=0x1;
> > ret_mid ^=0;
> > ret_low ^=0x7;
> > }
> >
> > if((ret_low & 0xc) == 0) ret_low |= 0x8;
> > if((ret_low & 0x40) == 0 && (ret_mid & 0x1) == 0) ret_low |= 0x80;
> > if((ret_mid & 0xa) == 0) ret_mid |= 0x4;
> > if((ret_mid & 0x50) == 0) ret_mid |= 0x20;
> > if((ret_high & 0x1) == 0) ret_high |= 0x2;
> >
> >
> > VAR(secondary[0]) = ret_high;
> > VAR(secondary[1]) = ret_mid;
> > VAR(secondary[2]) = ret_low;
> >
> > }
> >
> > char decodeData(){
> >
> > //strip the data
> > char ret_high = 0;
> > char ret_low = 0;
> > char val, val2, output;
> >
> >
> > ret_high = (char)((VAR(secondary)[0] << 4) & 0x10);
> > ret_high |= (char)((VAR(secondary)[1] >> 4) & 0xc);
> > ret_high |= (char)((VAR(secondary)[1] >> 3) & 0x3);
> > ret_low = (char)((VAR(secondary)[1] << 6) & 0xc0);
> > ret_low |= (char)((VAR(secondary)[2] >> 1) & 0x38);
> > ret_low |= (char)(VAR(secondary)[2] & 0x7);
> > //check the data
> > val = ret_low;
> > val2 = ret_high;
> > output = 0;
> > if((val & 0x1) != 0) output ^= 0x1;
> > if((val & 0x2) != 0) output ^= 0x2;
> > if((val & 0x4) != 0) output ^= 0x4;
> > if((val & 0x8) != 0) output ^= 0x8;
> > if((val & 0x10) != 0) output ^= 0x10;
> > if((val & 0x20) != 0) output ^= 0x1f;
> > if((val & 0x40) != 0) output ^= 0x1c;
> > if((val & 0x80) != 0) output ^= 0x1a;
> > if((val2 & 0x1) != 0) output ^= 0x19;
> > if((val2 & 0x2) != 0) output ^= 0x16;
> > if((val2 & 0x4) != 0) output ^= 0x15;
> > if((val2 & 0x8) != 0) output ^= 0xb;
> > if((val2 & 0x10) != 0) output ^= 0x7;
> > if(output == 0){}
> > else if(output == 0x1) { val ^= 0x1;}
> > else if(output == 0x2) { val ^= 0x2; }
> > else if(output == 0x4) { val ^= 0x4; }
> > else if(output == 0x8) { val ^= 0x8; }
> > else if(output == 0x10) { val ^= 0x10;}
> > else if(output == 0x1f) { val ^= 0x20;}
> > else if(output == 0x1c) { val ^= 0x40;}
> > else if(output == 0x1a) { val ^= 0x80;}
> > else if(output == 0x19) { val2 ^= 0x1; }
> > else if(output == 0x16) { val2 ^= 0x2; }
> > else if(output == 0x15) { val2 ^= 0x4; }
> > else if(output == 0xb) { val2 ^= 0x8; }
> > else if(output == 0x7) { val2 ^= 0x10;}
> >
> > //pull off the data bits
> > output = (char)((val >> 5) & 0x7);
> > output |= ((char)val2 << 3) & 0xf8;
> > return output;
> > }
> >
> > char TOS_EVENT(SIGNAL_DATA_READY)(int data){
> > if(VAR(s_count) < 4){
> > if(data == 0) data = 0x3ff;
> >
> > VAR(strength) += data;
> >
> > // BVL
> > // if(data > VAR(strength))
> > // VAR(strength)=data;
> > // ---
> >
> > VAR(s_count) ++;
> > }
> >
> > // XXX
> > //if (++VAR(led_state) % 2) CLR_GREEN_LED_PIN();
> > //else SET_GREEN_LED_PIN();
> > // XXX
> >
> > return 1;
> > }
> >
> >
> >
> >
> >
> >
> >
