diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 7c486f1..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,67 +0,0 @@
-# Continuous Integration (CI) is the practice, in software
-# engineering, of merging all developer working copies with a shared mainline
-# several times a day < https://docs.platformio.org/page/ci/index.html >
-#
-# Documentation:
-#
-# * Travis CI Embedded Builds with PlatformIO
-#   < https://docs.travis-ci.com/user/integration/platformio/ >
-#
-# * PlatformIO integration with Travis CI
-#   < https://docs.platformio.org/page/ci/travis.html >
-#
-# * User Guide for `platformio ci` command
-#   < https://docs.platformio.org/page/userguide/cmd_ci.html >
-#
-#
-# Please choose one of the following templates (proposed below) and uncomment
-# it (remove "# " before each line) or use own configuration according to the
-# Travis CI documentation (see above).
-#
-
-
-#
-# Template #1: General project. Test it using existing `platformio.ini`.
-#
-
-# language: python
-# python:
-#     - "2.7"
-#
-# sudo: false
-# cache:
-#     directories:
-#         - "~/.platformio"
-#
-# install:
-#     - pip install -U platformio
-#     - platformio update
-#
-# script:
-#     - platformio run
-
-
-#
-# Template #2: The project is intended to be used as a library with examples.
-#
-
-# language: python
-# python:
-#     - "2.7"
-#
-# sudo: false
-# cache:
-#     directories:
-#         - "~/.platformio"
-#
-# env:
-#     - PLATFORMIO_CI_SRC=path/to/test/file.c
-#     - PLATFORMIO_CI_SRC=examples/file.ino
-#     - PLATFORMIO_CI_SRC=path/to/test/directory
-#
-# install:
-#     - pip install -U platformio
-#     - platformio update
-#
-# script:
-#     - platformio ci --lib="." --board=ID_1 --board=ID_2 --board=ID_N
diff --git a/.vscode/extensions.json b/.vscode/extensions.json
deleted file mode 100644
index e80666b..0000000
--- a/.vscode/extensions.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-    // See http://go.microsoft.com/fwlink/?LinkId=827846
-    // for the documentation about the extensions.json format
-    "recommendations": [
-        "platformio.platformio-ide"
-    ]
-}
diff --git a/CVReader.ino b/CVReader.ino
new file mode 100644
index 0000000..caa114e
--- /dev/null
+++ b/CVReader.ino
@@ -0,0 +1,67 @@
+#include "DCCWaveform.h"
+#include "DIAG.h"
+bool verifyCV(int cv, byte bValue);
+int readCv(int cv);
+const int cvnums[]={1,2,3,4,5,17,18,19,21,22,29};
+
+void setup() {
+  Serial.begin(115200);
+  DCCWaveform::begin();
+  Serial.println(F("CVReader"));
+
+  DIAG(F("\n===================================\n"));
+  
+  for (byte x=0;x<sizeof(cvnums)/sizeof(cvnums[0]);x++) {
+    DIAG(F("\n\nCV VERIFICATION %d = %s\n"),cvnums[x],readCV(cvnums[x])>=0?"OK":"FAIL"); 
+  }
+  
+ DIAG(F("\nProgram complete, press reset to retry"));
+}
+
+void loop() {
+  
+}
+
+byte cv1(byte opcode, int cv) {
+  cv--;
+  return (highByte(cv) & (byte)0x03) | opcode;
+}
+byte cv2(int cv) {
+  cv--;
+  return lowByte(cv);
+}
+
+//// The functions below are lifted from the DCCApi for easy testing and experimentation.
+// Once reliable, tha DCCApi should be updated to match 
+bool verifyCV(int cv, byte value) {
+   
+   delay(2);  // allow for decoder to quiesce latest pulse
+   
+   
+   byte message[] = {
+    cv1(0x74,cv)  ,   // set-up to re-verify entire byte
+    cv2(cv),
+    value
+    };
+  
+  DCCWaveform::progTrack.schedulePacket(message, sizeof(message), 5);  
+  return DCCWaveform::progTrack.getAck();
+}
+
+int readCV(int cv) 
+{
+  
+  byte message[]={  cv1(0x78,cv)  ,   // any CV>1023 will become modulus(1024) due to bit-mask of 0x03
+                   cv2(cv),
+                   0};    // trailing zero will be updated in loop below
+
+  byte value = 0;
+
+  for (int i = 0; i<8; i++) {
+    message[2] = 0xE8 + i;
+    DCCWaveform::progTrack.schedulePacket(message,sizeof(message), 4);                // NMRA recommends 5 rerad packets
+    value+= (DCCWaveform::progTrack.getAck()<<i);
+  }
+  DIAG(F("\n*** READ CV %d = %d ******\n"),cv,value);
+  return verifyCV(cv,value)?value:-1;
+}
diff --git a/DCCWaveform.cpp b/DCCWaveform.cpp
new file mode 100644
index 0000000..97af356
--- /dev/null
+++ b/DCCWaveform.cpp
@@ -0,0 +1,235 @@
+#include <Arduino.h>
+#include <TimerThree.h>
+#include "DCCWaveform.h"
+#include "DIAG.h"
+DCCWaveform  DCCWaveform::mainTrack(MAIN_POWER_PIN,MAIN_SIGNAL_PIN,MAIN_SENSE_PIN,PREAMBLE_BITS_MAIN,true);
+DCCWaveform  DCCWaveform::progTrack(PROG_POWER_PIN,PROG_SIGNAL_PIN,PROG_SENSE_PIN,PREAMBLE_BITS_PROG,false);
+
+void DCCWaveform::begin() {
+  
+   Timer3.initialize(58);
+   Timer3.disablePwm(MAIN_SIGNAL_PIN);
+   Timer3.disablePwm(PROG_SIGNAL_PIN);
+   Timer3.attachInterrupt(interruptHandler);
+   mainTrack.beginTrack();
+   progTrack.beginTrack();   
+}
+ 
+ void DCCWaveform::loop() {
+   mainTrack.checkPowerOverload();
+   progTrack.checkPowerOverload();
+ }
+ 
+
+// static //
+void DCCWaveform::interruptHandler() {
+   // call the timer edge sensitive actions for progtrack and maintrack
+   bool mainCall2=mainTrack.interrupt1();
+   bool progCall2=progTrack.interrupt1();
+   
+   // call (if necessary) the procs to get the current bits
+   // these must complete within 50microsecs of the interrupt
+   // but they are only called ONCE PER BIT TRANSMITTED 
+   // after the rising edge of the signal
+   if (mainCall2) mainTrack.interrupt2();
+   if (progCall2) progTrack.interrupt2();
+}
+
+
+// An instance of this class handles the DCC transmissions for one track. (main or prog)
+// Interrupts are marshalled via the statics.
+// A track has a current transmit buffer, and a pending buffer.
+// When the current buffer is exhausted, either the pending buffer (if there is one waiting) or an idle buffer. 
+
+
+// This bitmask has 9 entries as each byte is trasmitted as a zero + 8 bits.
+const byte bitMask[]={0x00,0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01};
+
+
+DCCWaveform::DCCWaveform(byte powerPinNo, byte directionPinNo, byte sensePinNo, byte preambleBits, bool isMain) {
+   // establish appropriate pins 
+   powerPin=Arduino_to_GPIO_pin(powerPinNo);
+   directionPin=Arduino_to_GPIO_pin(directionPinNo);
+   sensePin=sensePinNo;
+   isMainTrack=isMain;
+   packetPending=false;
+   memcpy(transmitPacket,idlePacket,sizeof(idlePacket));
+   state=0;
+   requiredPreambles=preambleBits;
+   bytes_sent=0;
+   bits_sent=0;
+   nextSampleDue=0;
+}
+ void DCCWaveform::beginTrack() {
+   pinMode2f(powerPin,OUTPUT);
+   pinMode2f(directionPin,OUTPUT);
+   pinMode(sensePin,INPUT);
+   setPowerMode(POWERMODE::ON); 
+   DIAG(F("\nTrack started sensePin=%d\n"),sensePin); 
+ }
+
+ POWERMODE DCCWaveform::getPowerMode() {
+  return powerMode;
+ }
+
+ void DCCWaveform::setPowerMode(POWERMODE mode) {
+  powerMode=mode;
+  digitalWrite2f(powerPin, mode==POWERMODE::ON ? HIGH:LOW);
+  if (mode==POWERMODE::ON) schedulePacket(resetMessage,2,20); 
+ }
+ 
+ 
+void DCCWaveform::checkPowerOverload() {
+  if (millis()<nextSampleDue) return;
+  int current;
+  int delay;
+  
+  switch (powerMode) {
+    case POWERMODE::OFF: 
+      delay=POWER_SAMPLE_OFF_WAIT;
+      break;
+   case POWERMODE::ON: 
+      // Check current  
+      current=analogRead(sensePin);
+      if (current < POWER_SAMPLE_MAX)  delay=POWER_SAMPLE_ON_WAIT;
+      else {
+        setPowerMode(POWERMODE::OVERLOAD);
+        DIAG(F("\n*** %s TRACK POWER OVERLOAD pin=%d current=%d max=%d ***\n"),isMainTrack?"MAIN":"PROG",sensePin,current,POWER_SAMPLE_MAX);
+        delay=POWER_SAMPLE_OVERLOAD_WAIT;
+      }
+      break;
+   case POWERMODE::OVERLOAD:
+      // Try setting it back on after the OVERLOAD_WAIT
+      setPowerMode(POWERMODE::ON);
+      delay=POWER_SAMPLE_ON_WAIT;
+      break;
+    default:
+      delay=999;  // cant get here..meaningless statement to avoid compiler warning.  
+  }
+  nextSampleDue=millis()+delay;
+}
+
+
+
+
+
+// process time-edge sensitive part of interrupt
+// return true if second level required  
+bool DCCWaveform::interrupt1() {
+  // NOTE: this must consume transmission buffers even if the power is off 
+  // otherwise can cause hangs in main loop waiting for the pendingBuffer. 
+  switch (state) {
+    case 0:  // start of bit transmission
+      digitalWrite2f(directionPin, HIGH);
+      state = 1;
+      return true; // must call interrupt2
+
+    case 1:  // 58Ms after case 0
+      if (currentBit) {
+        digitalWrite2f(directionPin, LOW);
+        state = 0;
+      }
+      else state = 2;
+      break;
+    case 2:  digitalWrite2f(directionPin, LOW);
+      state = 3;
+      break;
+    case 3:  state = 0;
+    break;
+  }
+  return false;
+ 
+}
+void DCCWaveform::interrupt2() {
+  // set currentBit to be the next bit to be sent.
+  
+  if (remainingPreambles > 0 ) {
+    currentBit=true;
+    remainingPreambles--;
+    return;
+  }
+  
+  // beware OF 9-BIT MASK  generating a zero to start each byte   
+  currentBit=transmitPacket[bytes_sent] & bitMask[bits_sent];
+  bits_sent++;
+
+  // If this is the last bit of a byte, prepare for the next byte 
+  
+  if (bits_sent==9) { // zero followed by 8 bits of a byte
+      //end of Byte
+      bits_sent=0;
+      bytes_sent++;
+      // if this is the last byte, prepere for next packet
+      if (bytes_sent >= transmitLength) { 
+         // end of transmission buffer... repeat or switch to next message
+        bytes_sent = 0;
+        remainingPreambles=requiredPreambles;
+
+        if (transmitRepeats > 0) {
+          transmitRepeats--;
+        }
+        else if (packetPending) {
+          // Copy pending packet to transmit packet
+          for (int b=0;b<pendingLength;b++) transmitPacket[b]= pendingPacket[b];
+          transmitLength=pendingLength;
+          transmitRepeats=pendingRepeats;
+          packetPending=false;
+        }
+        else {
+          // Fortunately reset and idle packets are the same length
+         memcpy( transmitPacket,isMainTrack?idlePacket:resetPacket, sizeof(idlePacket));
+          transmitLength=sizeof(idlePacket);
+          transmitRepeats=0;
+        }
+      }
+    }
+  }
+
+
+  // Wait until there is no packet pending, then make this pending  
+void DCCWaveform::schedulePacket(const byte buffer[], byte byteCount, byte repeats) {
+    if (byteCount>=MAX_PACKET_SIZE) return; // allow for chksum
+    while(packetPending) delay(1);
+    
+    byte checksum=0;
+    for (int b=0;b<byteCount; b++) {
+      checksum^=buffer[b];
+      pendingPacket[b]=buffer[b];
+    }
+    pendingPacket[byteCount]=checksum;
+    pendingLength=byteCount+1;
+    pendingRepeats=repeats;
+    packetPending=true;
+  }
+ 
+
+
+bool DCCWaveform::getAck()
+{
+  
+   if (isMainTrack) return false; // cant do this on main track
+ 
+  while(packetPending) delay(1); // wait until transmitter has gont into reset packets
+  delay(20); // time for enough resets  
+  unsigned long timeout=millis()+ACK_TIMEOUT;
+  int maxCurrent=0;
+  bool result=false;
+  int upsamples=0;
+  int downsamples=0;
+  while(result==false && timeout>millis()) {
+    upsamples++;
+    delay(1);
+    int current=analogRead(sensePin);
+    maxCurrent=max(maxCurrent,current);
+    result=current > ACK_MIN_PULSE;
+  }
+  if (result) while( true) {
+     downsamples++;
+     delay(1);
+     int current=analogRead(sensePin);
+     maxCurrent=max(maxCurrent,current);
+     if (current<= ACK_MAX_NOT_PULSE)break;
+  }
+  DIAG(F("\nack=%d  max=%d, up=%d, down=%d "),result,maxCurrent, upsamples,downsamples);
+  return result;
+}
diff --git a/DCCWaveform.h b/DCCWaveform.h
new file mode 100644
index 0000000..e6d781b
--- /dev/null
+++ b/DCCWaveform.h
@@ -0,0 +1,89 @@
+#include <DIO2.h>
+// This hardware configuration would normally be setup in a .h file elsewhere
+const byte MAIN_POWER_PIN=3;
+const byte MAIN_SIGNAL_PIN=12;
+const byte MAIN_SENSE_PIN=A0;
+
+const byte PROG_POWER_PIN=11;
+const byte PROG_SIGNAL_PIN=13;
+const byte PROG_SENSE_PIN=A1;
+
+const int  POWER_SAMPLE_MAX=300;
+const int  POWER_SAMPLE_ON_WAIT=100;
+const int  POWER_SAMPLE_OFF_WAIT=1000;
+const int  POWER_SAMPLE_OVERLOAD_WAIT=4000;
+
+
+// ACK current analogRead values (vary depending on motor shield and cpu voltage)
+const int   ACK_TIMEOUT = 5 ;  // millis getAck is prepared to wait for a signal
+const int   ACK_MAX_NOT_PULSE = 10 ;  // current below which this is NOT a pulse any more
+const int   ACK_MIN_PULSE = 50 ;   // current above which a pulse is recognised
+
+const int   PREAMBLE_BITS_MAIN=16;
+const int   PREAMBLE_BITS_PROG=22;        
+
+const byte   MAX_PACKET_SIZE=12;
+// NOTE: static functions are used for the overall controller, then 
+// one instance is created for each track.
+
+
+enum class POWERMODE { OFF, ON, OVERLOAD };
+const byte idleMessage[]={0xFF,0x00};
+const byte resetMessage[]={0x00,0x00};
+const byte idlePacket[]={0xFF,0x00,0xFF};
+const byte resetPacket[]={0x00,0x00,0x00};
+
+class DCCWaveform {
+  public:
+   DCCWaveform(byte powerPinNo, byte directionPinNo, byte sensePinNo, byte preambleBits, bool isMain);
+   static void begin();
+   static void loop();
+   static DCCWaveform  mainTrack;
+   static DCCWaveform  progTrack; 
+   
+  void beginTrack();
+  void setPowerMode(POWERMODE);
+  POWERMODE getPowerMode();
+  void checkPowerOverload();
+  void schedulePacket(const byte buffer[], byte byteCount, byte repeats);
+  volatile bool packetPending;
+  bool  startAckProcess();
+  bool  getAck();
+
+  
+  private:
+ 
+  static void interruptHandler();
+  bool interrupt1();
+  void interrupt2();
+  
+  POWERMODE powerMode;
+
+// Transmission controller
+  byte transmitPacket[MAX_PACKET_SIZE];  // packet being transmitted
+  byte transmitLength;
+  byte transmitRepeats;      // remaining repeats of transmission
+  byte remainingPreambles;
+  byte requiredPreambles;
+  bool currentBit;           // bit to be transmitted
+
+  byte bits_sent;           // 0-8 (yes 9 bits) sent for current byte  
+  byte bytes_sent;          // number of bytes sent from transmitPacket
+  
+  byte state;               // wave generator state machine
+  
+  byte pendingPacket[MAX_PACKET_SIZE];
+  byte pendingLength;
+  byte pendingRepeats;
+
+  // Hardware pins
+  GPIO_pin_t directionPin;
+  GPIO_pin_t powerPin;
+ 
+  // current sampling 
+  bool isMainTrack;
+  byte sensePin;
+  unsigned long nextSampleDue;
+  int ackBaseCurrent;
+  
+};
diff --git a/DIAG.cpp b/DIAG.cpp
new file mode 100644
index 0000000..580010f
--- /dev/null
+++ b/DIAG.cpp
@@ -0,0 +1,27 @@
+#include <arduino.h>
+#include <stdarg.h>
+
+void Serialprint(const __FlashStringHelper* input...) {
+  // thanks to Jan Turoň  https://arduino.stackexchange.com/questions/56517/formatting-strings-in-arduino-for-output
+
+  va_list args;
+  va_start(args, input);
+  char* flash=(char*)input;
+  for(int i=0; ; ++i) {
+    char c=pgm_read_byte_near(flash+i);
+    if (c=='\0') return;
+    if(c!='%') { Serial.print(c); continue; }
+    i++;
+    c=pgm_read_byte_near(flash+i);
+    switch(c) {
+      case '%': Serial.print('%'); break;
+      case 's': Serial.print(va_arg(args, char*)); break;
+      case 'd': Serial.print(va_arg(args, int), DEC); break;
+      case 'b': Serial.print(va_arg(args, int), BIN); break;
+      case 'o': Serial.print(va_arg(args, int), OCT); break;
+      case 'x': Serial.print(va_arg(args, int), HEX); break;
+      case 'f': Serial.print(va_arg(args, double), 2); break;
+    }
+  }
+  va_end(args);
+}
diff --git a/DIAG.h b/DIAG.h
new file mode 100644
index 0000000..8ac3fdd
--- /dev/null
+++ b/DIAG.h
@@ -0,0 +1,5 @@
+void Serialprint(const __FlashStringHelper* input...);
+#ifndef DIAG_ENABLED
+ #define DIAG_ENABLED true
+#endif
+#define DIAG if (DIAG_ENABLED) Serialprint
diff --git a/include/README b/include/README
deleted file mode 100644
index 194dcd4..0000000
--- a/include/README
+++ /dev/null
@@ -1,39 +0,0 @@
-
-This directory is intended for project header files.
-
-A header file is a file containing C declarations and macro definitions
-to be shared between several project source files. You request the use of a
-header file in your project source file (C, C++, etc) located in `src` folder
-by including it, with the C preprocessing directive `#include'.
-
-```src/main.c
-
-#include "header.h"
-
-int main (void)
-{
- ...
-}
-```
-
-Including a header file produces the same results as copying the header file
-into each source file that needs it. Such copying would be time-consuming
-and error-prone. With a header file, the related declarations appear
-in only one place. If they need to be changed, they can be changed in one
-place, and programs that include the header file will automatically use the
-new version when next recompiled. The header file eliminates the labor of
-finding and changing all the copies as well as the risk that a failure to
-find one copy will result in inconsistencies within a program.
-
-In C, the usual convention is to give header files names that end with `.h'.
-It is most portable to use only letters, digits, dashes, and underscores in
-header file names, and at most one dot.
-
-Read more about using header files in official GCC documentation:
-
-* Include Syntax
-* Include Operation
-* Once-Only Headers
-* Computed Includes
-
-https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html
diff --git a/lib/README b/lib/README
deleted file mode 100644
index 6debab1..0000000
--- a/lib/README
+++ /dev/null
@@ -1,46 +0,0 @@
-
-This directory is intended for project specific (private) libraries.
-PlatformIO will compile them to static libraries and link into executable file.
-
-The source code of each library should be placed in a an own separate directory
-("lib/your_library_name/[here are source files]").
-
-For example, see a structure of the following two libraries `Foo` and `Bar`:
-
-|--lib
-|  |
-|  |--Bar
-|  |  |--docs
-|  |  |--examples
-|  |  |--src
-|  |     |- Bar.c
-|  |     |- Bar.h
-|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
-|  |
-|  |--Foo
-|  |  |- Foo.c
-|  |  |- Foo.h
-|  |
-|  |- README --> THIS FILE
-|
-|- platformio.ini
-|--src
-   |- main.c
-
-and a contents of `src/main.c`:
-```
-#include <Foo.h>
-#include <Bar.h>
-
-int main (void)
-{
-  ...
-}
-
-```
-
-PlatformIO Library Dependency Finder will find automatically dependent
-libraries scanning project source files.
-
-More information about PlatformIO Library Dependency Finder
-- https://docs.platformio.org/page/librarymanager/ldf.html
diff --git a/platformio.ini b/platformio.ini
deleted file mode 100644
index d49d13f..0000000
--- a/platformio.ini
+++ /dev/null
@@ -1,14 +0,0 @@
-; PlatformIO Project Configuration File
-;
-;   Build options: build flags, source filter
-;   Upload options: custom upload port, speed and extra flags
-;   Library options: dependencies, extra library storages
-;   Advanced options: extra scripting
-;
-; Please visit documentation for the other options and examples
-; https://docs.platformio.org/page/projectconf.html
-
-[env:megaatmega1280]
-platform = atmelavr
-board = megaatmega1280
-framework = arduino
diff --git a/src/main.cpp b/src/main.cpp
deleted file mode 100644
index 2004045..0000000
--- a/src/main.cpp
+++ /dev/null
@@ -1,10 +0,0 @@
-#include <Arduino.h>
-
-void setup() {
-  Serial.begin(115200);
-  Serial.println(F("CVReader"));
-}
-
-void loop() {
-  // put your main code here, to run repeatedly:
-}
\ No newline at end of file
diff --git a/test/README b/test/README
deleted file mode 100644
index df5066e..0000000
--- a/test/README
+++ /dev/null
@@ -1,11 +0,0 @@
-
-This directory is intended for PIO Unit Testing and project tests.
-
-Unit Testing is a software testing method by which individual units of
-source code, sets of one or more MCU program modules together with associated
-control data, usage procedures, and operating procedures, are tested to
-determine whether they are fit for use. Unit testing finds problems early
-in the development cycle.
-
-More information about PIO Unit Testing:
-- https://docs.platformio.org/page/plus/unit-testing.html