// PPM Encoder Analog Add-ons for Devo7e
// For use with Digispark
// J. Diehl 12/07/2015
// Based on a sketch by Ian Johnston 29/04/2010
//  modified by Epyon and Cereal_Killer
// Version 4.0 
// Low cost way to add extra POT's to any radio that accepts PPM input for <$15
//  using a Digispark, 2 POT's, and a 3-way and 2-way switch.  Visit DeviationTX.com for info. 
// 5k POT's on JP3-0 and -3
// 3-way (On-off-On) switch on JP3-2 and-4
// 2-way (On-off) switch on JP3-5
// PPM output on JP3-2
// PPM inout to tip of 3.5 mono jack, this is the black wire on your Devo 7E DSC port

int potPin_A1 = 2;  //Declare potPin_A1 to be analog A1, pin 2 - no conflicts
int potPin_A2 = 4;  //Declare potPin_A2 to be analog A2, pin 4 - used in USB
int AI_Raw_A1;      // Analog In raw var - 0->1023
int AI_Raw_A2;      // Analog In raw var - 0->1023

byte swPin_D1 = 0;   //Declare swPin_D1 to be Digital pin pin 0 - no conflicts
byte swPin_D2 = 3;   //Declare swPin_D2 to be Digital pin pin 3 - used in USB 
byte swPin_D3 = 5;   //Declare swPin_D3 to be Digital pin pin 5 - also NRESET

int outPinPPM = 1;   // Declare ppmPin to be pin pin 1; LED is on this line

int Fixed_uS = 300;       // PPM frame fixed LOW phase
int pulseMin = 750;       // pulse minimum width minus start in uS
int pulseMax = 1700;      // pulse maximum width in uS

int pulseMid = pulseMin + (pulseMax - pulseMin) / 2;
float adjustRng = ( pulseMax - pulseMin ) / 1023.0; // adjust range from 0-1023

int A1_uS  = pulseMin;     // Analog 1 uS var
int A2_uS  = pulseMin;     // Analog 2 uS var
int sw1_uS = pulseMin;     // 3-way Switch 1 combines result from swPin_D1 and D2
int sw2_uS = pulseMin;     // 2-way Switch 2 results from swPin_D3


void setup() {
  pinMode(potPin_A1, INPUT);    //set potPin_A1 to be an input
  pinMode(potPin_A2, INPUT);    //set potPin_A2 to be an input
  pinMode(swPin_D1, INPUT);     //set swPin_D1 to be an input
  digitalWrite(swPin_D1, HIGH); // turn on pull-up resistor
  pinMode(swPin_D2, INPUT);     //set swPin_D2 to be an input
  digitalWrite(swPin_D2, HIGH); // turn on pull-up resistor
  pinMode(swPin_D3, INPUT);     //set swPin_D3 to be an input
  digitalWrite(swPin_D3, HIGH); // turn on pull-up resistor

  pinMode(outPinPPM, OUTPUT);   //set ppmPin to be an OUTPUT
  digitalWrite(outPinPPM, HIGH);// turn on LED
/*
 // Setup timer
  TCCR1A = B00110001; // Compare register B used in mode '3'
  TCCR1B = B00010010; // WGM13 and CS11 set to 1
  TCCR1C = B00000000; // All set to 0
  TIMSK1 = B00000010; // Interrupt on compare B
  TIFR1  = B00000010; // Interrupt on compare B
  OCR1A = 22000; // 22mS PPM output refresh
  OCR1B = 1000;
*/
 //For Digispark use Timer0
TCCR0A = (1 << WGM01);             //CTC mode
TCCR0B = (2 << CS00);              //div8
OCR0A = F_CPU/8 * 0.000050 - 1;    //50ms -- need to change to 22us compare value
TIMSK |= (1<<OCIE0A);              //if you want interrupt


 //  Serial.begin(9600);      // turn on Serial Port

}

ISR(TIMER0_COMPA_vect) {
    ppmoutput(); // Jump to ppmoutput subroutine
}


void ppmoutput() { // PPM output sub

 // Channel 1 - Analog 1
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(A1_uS);  // Hold for A1_uS microseconds 

 // Channel 2 - Analog 2
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(A2_uS);  // Hold for A2_uS microseconds 

 // Channel 3 - Switch 1 3-way
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(sw1_uS);     // Hold for sw1_uS microseconds 

 // Channel 4 - Switch 2 2-way
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(sw2_uS);     // Hold for sw2_uS microseconds 

 // Synchro pulse
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);  // Start Synchro pulse

/* Serial.print("You are writing a value of ");  //for debugging print your values
 Serial.print(A1_uS);
 Serial.print("  ");
 Serial.print(A2_uS);
 Serial.print("  ");
 Serial.print(sw1_uS);
 Serial.print("  ");
 Serial.print(sw2_uS);
 Serial.print("  ");

 Serial.println(" End");
*/
}


void loop() {

 // logic to read each analog input
 // Read analog pins
   AI_Raw_A1 = analogRead(potPin_A1);   // Analog Pot 1
   AI_Raw_A2 = analogRead(potPin_A2);   // Analog Pot 2
   
 // Map analog inputs to PPM rates for each of the channels
 //  compensate for analog 0-1023 vs expected 750-1700
 //  TEST with the MAP command
   A1_uS = map (AI_Raw_A1,0,1023,pulseMin,pulseMax);
   A2_uS = map (AI_Raw_A2,0,1023,pulseMin,pulseMax);
 //  A1_uS = AI_Raw_A1 * adjustRng + pulseMin;
 //  A2_uS = AI_Raw_A2 * adjustRng + pulseMin;

 // Check limits
  A1_uS = constrain (A1_uS, pulseMin, pulseMax);
  A2_uS = constrain (A2_uS, pulseMin, pulseMax);
/*  if (A1_uS <= pulseMin) A1_uS = pulseMin;  // Min
  if (A1_uS >= pulseMax) A1_uS = pulseMax;  // Max   
  if (A2_uS <= pulseMin) A2_uS = pulseMin;  // Min
  if (A2_uS >= pulseMax) A2_uS = pulseMax;  // Max 
*/
  if (digitalRead(swPin_D1) != 1) { // 3-way Switch 1
           sw1_uS = pulseMin;
  } else {
           if (digitalRead(swPin_D2) != 1 ) {
            sw1_uS = pulseMax;
  }        else {
            sw1_uS = pulseMid;
            }
  }
  if (digitalRead(swPin_D3) != 1) { // 2-way Switch 2
           sw2_uS = pulseMin;
  } else {
           sw2_uS = pulseMax;        
  }
}