add simple serial receive and transmit test for uint8_t, uint16_t, int16_t and float

serialtest_receiver_processing/serialtest_receiver_processing.pde

@@ -0,0 +1,51 @@
+import processing.serial.*;
+
+Serial serialport;
+
+void setup() {
+  printArray(Serial.list());
+  serialport = new Serial(this, Serial.list()[2], 9600);
+  println("start");
+}
+
+void draw() {
+  byte[] inBuffer = new byte[9];
+  while(serialport.available()>0) {
+    inBuffer = serialport.readBytes();
+    serialport.readBytes(inBuffer);
+    if (inBuffer!= null) {
+      int counter= inBuffer[0];
+      int value1= extract_uint16_t(inBuffer,1);
+      int value2= extract_int16_t(inBuffer,3);
+      float floatvalue = extract_float(inBuffer,5);
+      println("counter="+counter);
+      println("value1="+value1);
+      println("value2="+value2);
+      println("floatvalue="+floatvalue);
+    }
+    
+  }
+}
+
+public int extract_uint16_t(byte array[], int startbyte) {
+  return ((int)array[startbyte] & 0xff) | ((int)array[startbyte+1] & 0xff)<<8;
+}
+
+public int extract_int16_t(byte array[], int startbyte) {
+  if ( ((int)array[startbyte+1] & 0x80) == 0x00 ) { //2's complement, not negative
+    return ( ((int)array[startbyte] & 0xff) | ((int)array[startbyte+1] & 0x7f)<<8 );
+  }else{ //value is negative
+    return -32768 + ( ((int)array[startbyte] & 0xff) | ((int)array[startbyte+1] & 0x7f)<<8 );
+  }
+}
+
+public float extract_float(byte array[], int startbyte) {
+    int MASK = 0xff;
+    int bits = 0;
+    int i = startbyte+3; //+3 because goes backwards and has 4 bytes
+    for (int shifter = 3; shifter >= 0; shifter--) {
+    bits |= ((int) array[i] & MASK) << (shifter * 8);
+    i--;
+    }
+    return Float.intBitsToFloat(bits);
+}