Corrected and error where the data bit is captured

to stop overun errors at th eend of bytes causing
the whole packet to be dumped.

It shoudl read the last bit of the last byte without, 
what happens after that wrecking it.

Author: robwlakes

DebugManchester.ino

@@ -1,16 +1,12 @@
 /* 
  Manchester Decoding, reading by delay rather than interrupt
- Rob Ward July 2014
+ Rob Ward August 2014
  This example code is in the public domain.
  Use at your own risk, I will take no responsibility for any loss whatsoever its deployment.
  Visit https://github.com/robwlakes/ArduinoWeatherOS for the latest version and
- documentation. Filename: DebugManchester.ino ReadMe: DebugMan.md
-
- NB: Choosing the wrong polarity will still provide "data", but will be incorrect
- even thought the two delays are working properly!!!
- Remember to check both Polarity settings for sensible data.
+ documentation. Filename: DebugManchester.ino
  
- DebugVersion_09, 28tyh July 2014
+ DebugVersion_10, 1stAugust 2014
  
  */
 
@@ -19,11 +15,10 @@ int RxPin           = 8;   //The number of signal from the Rx
 int ledPin          = 13;  //The number of the onboard LED pin
 
 // Variables for Manchester Receiver Logic:
-word    sDelay     = 240;  //Small Delay about 1/4 of bit duration try like 220 to 480
-word    lDelay     = 480;  //Long Delay about 1/2 of bit duration  try like 440 to 880, 1/4 + 1/2 = 3/4
+word    sDelay     = 250;  //Small Delay about 1/4 of bit duration  try like 250 to 500
+word    lDelay     = 500;  //Long Delay about 1/2 of bit duration  try like 500 to 1000, 1/4 + 1/2 = 3/4
 byte    polarity   = 1;    //0 for lo->hi==1 or 1 for hi->lo==1 for Polarity, sets tempBit at start
-byte    tempBit       ;    //Reflects the required transition polarity
-byte    bitState      ;    //State of the RxPin 3/4 way through Bit Waveform
+byte    tempBit    = 1;    //Reflects the required transition polarity
 byte    discards   = 0;    //how many leading "bits" need to be dumped, usually just a zero if anything eg discards=1
 boolean firstZero  = false;//has it processed the first zero yet?  This a "sync" bit.
 boolean noErrors   = true; //flags if signal does not follow Manchester conventions
@@ -33,7 +28,7 @@ byte    headerHits = 0;    //Counts the number of "1"s to determine a header
 //Variables for Byte storage
 byte    dataByte   = 0;    //Accumulates the bit information
 byte    nosBits    = 0;    //Counts to 8 bits within a dataByte
-byte    maxBytes   = 6;    //Set the bytes collected after each header. NB if set too high, any end noise will cause an error
+byte    maxBytes   = 5;    //Set the bytes collected after each header. NB if set too high, any end noise will cause an error
 byte    nosBytes   = 0;    //Counter stays within 0 -> maxBytes
 //Variables for multiple packets
 byte    bank       = 0;    //Points to the array of 0 to 3 banks of results from up to 4 last data downloads 
@@ -61,7 +56,7 @@ void setup() {
   Serial.begin(115200);//make it fast so it dumps quick!
   pinMode(RxPin, INPUT);
   pinMode(ledPin, OUTPUT);
-  Serial.println("Debug Manchester Version GIT-Hub V01");
+  Serial.println("Debug Manchester Version 09");
   lDelay=2*sDelay;//just to make sure the 1:2 ratio is established. They can have some other ratio if required
   Serial.print("Using a delay of 1/4 bitWaveform ");// +-15% and they still seem to work ok, pretty tolerant!
   Serial.print(sDelay,DEC);
@@ -91,7 +86,7 @@ void setup() {
 
 // Main routines, find header, then sync in with it, get a packet, and decode data in it, plus report any errors.
 void loop(){
-  tempBit=polarity^1; //these begin as opposites for each packet
+  tempBit=polarity^1; //these begin the opposites for a packet
   noErrors=true;
   firstZero=false;
   headerHits=0;
@@ -108,18 +103,16 @@ void loop(){
       noErrors=false;//something has gone wrong, polarity has changed too early, ie always an error
     }//exit and retry
     else{
-      //now grab the bitState before setting up for next bit & correct for polarity
-      bitState = tempBit ^ polarity;//Polarity=1, invert OR Polarity=0, ignore
-      //Now work on what the next bit waveform is going to be 
+      byte bitState = tempBit ^ polarity;//if polarity=1, invert the tempBit or if polarity=0, leave it alone.
       delayMicroseconds(lDelay);
       //now 1 quarter into the next bit pattern,
-      if(digitalRead(RxPin)==tempBit){ //if RxPin has NOT swapped, then next data bit value IS swapping
+      if(digitalRead(RxPin)==tempBit){ //if RxPin has not swapped, then bitWaveform is swapping
         //If the header is done, then it means data change is occuring ie 1->0, or 0->1
-        //data transition detection must swap, so it loops for the opposite transition in the next bit waveform
+        //data transition detection must swap, so it loops for the opposite transitions
         tempBit = tempBit^1;
-      }//end of detecting no transition at end of bit waveform
+      }//end of detecting no transition at end of bit waveform, ie end of previous bit waveform same as start of next bitwaveform
 
-      //Now process the tempBit state and interept data as definite 0 or 1's, (Polarity corrected by now) 
+      //Now process the tempBit state and make data definite 0 or 1's, allow possibility of Pos or Neg Polarity 
       if(bitState==1){ //1 data could be header or packet
         if(!firstZero){
           headerHits++;
@@ -142,7 +135,6 @@ void loop(){
           //we have our header, chewed up any excess and here is a zero
           if ((!firstZero)&&(headerHits>=headerBits)){ //if first zero, it has not been found previously
             firstZero=true;
-            //Serial.print("!");
           }//end of finding first zero
           add(bitState);
         }//end of dealing with a zero
@@ -170,7 +162,7 @@ void add(byte bitData){
       //Serial.print("B");
     }
     if(nosBytes==maxBytes){
-      hexBinDump();//for debug purposes dump out in hex and bainary
+      hexBinDump();//for debug purposes dump out in hex and binary
       //analyseData();//later on develop your own analysis routines
     }
   }
@@ -212,3 +204,18 @@ void eraseManchester(){
 
 
 
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