// PPM Encoder Analog Add-ons for Devo7e
// For use with Arduino Pro Mini 328P
// J. Diehl 14/08/2015
// Based on a sketch by Ian Johnston 29/04/2010
//  modified by Epyon and Cereal_Killer
// Version 2.31 
// Low cost way to add extra POT's to any radio that accepts PPM input for <$15
//  using an arduino nano and a few POT's, visit DeviationTX.com for info. 
// POT's on A1 and A2, optional Thumbwheel on A3, optional switches on D6-D10
//  Use On-Off-On switches on D6-D7, and D8-D9 for 3-way effect
// PPM output on D13
//  PPM inout to tip of 3.5 mono jack, this is the black wire on your Devo 7E DSC port
//  
//  This version disregards the Ring Shunt on D11 when shorted 
//
//  Original Sketch uses:
//  A1-3 Analog in for Pots 1, 2 and 3
//  D6-9 Digital in for up to 2x3-way
//  D3-4  Digital in for 1 3-way or 2 2-way
//  D11 - Devo7e DSC Port "Ring Shunt"  high; goes low when plug is inserted into DSC
//  D13 - PPM Output with LED


int potPin_A1= A1;  //Declare potPin_A1 to be analog pin A1
int potPin_A2= A2;  //Declare potPin_A2 to be analog pin A2
int potPin_A3= A3;  //Declare potPin_A3 to be analog pin A3
int AI_Raw_A1;        // Analog In raw var - 0->1023
int AI_Raw_A2;        // Analog In raw var - 0->1023
int AI_Raw_A3;        // Analog In raw var - 0->1023


byte swPin_D1= 6;   //Declare swPin_D1 to be Digital pin 6
byte swPin_D2= 7;   //Declare swPin_D2 to be Digital pin 7
byte swPin_D3= 8;   //Declare swPin_D3 to be Digital pin 8
byte swPin_D4= 9;   //Declare swPin_D4 to be Digital pin 9
byte swPin_D5= 3;  //Declare swPin_D5 to be Digital pin 3
byte swPin_D6= 4;  //Declare swPin_D6 to be Digital pin 4

int outPinPPM = 13;  // Declare ppmPin to be arduino pin 13

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 A3_uS = pulseMin;     // Analog 3 uS var
int sw1_uS = pulseMin;     // Switch 1 combines result from swPin_D1 and D2
int sw2_uS = pulseMin;     // Switch 2 combines result from swPin_D3 and D4
int sw3_uS = pulseMin;     // Switch 3 combines result from swPin_D5 and D6
int sw4_uS = pulseMin;     // Switch 4

ISR(TIMER1_COMPA_vect) {
    ppmoutput(); // Jump to ppmoutput subroutine
}


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(potPin_A3, INPUT);  //set potPin_A3 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(swPin_D4, INPUT);  //set swPin_D4 to be an input
  digitalWrite(swPin_D4, HIGH);  // turn on pull-up resistor
  pinMode(swPin_D5, INPUT);  //set swPin_D5 to be an input
  digitalWrite(swPin_D5, HIGH);  // turn on pull-up resistor
  pinMode(swPin_D6, INPUT);  //set swPin_D6 to be an input
  digitalWrite(swPin_D6, 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;


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

}

void ppmoutput() { // PPM output sub

// pinMode(outPinPPM, OUTPUT); //set ppmPin to be an OUTPUT
 
 // 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 - Analog 3
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(A3_uS);  // Hold for A3_uS microseconds 

// Channel 4 - Switch 1 3-way
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(sw1_uS);     // Hold for sw1_uS microseconds 

// Channel 5 - Switch 2 3-way
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(sw2_uS);     // Hold for sw2_uS microseconds 

// Channel 6 - Switch 3 3-way
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(sw3_uS);     // Hold for sw3_uS microseconds 

/*// Channel 7 - Switch 4
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(sw4_uS);     // Hold for sw4_uS microseconds 

// Channel 8 - Switch 5
  digitalWrite(outPinPPM, LOW);
  delayMicroseconds(Fixed_uS);    // Hold
  digitalWrite(outPinPPM, HIGH);
  delayMicroseconds(sw5_uS);     // Hold for sw5_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.println(A3_uS);
 Serial.print("  ");
 Serial.print(sw1_uS);
 Serial.print("  ");
 Serial.print(sw2_uS);
 Serial.print("  ");
 Serial.println(sw3_uS);
 Serial.print("  ");
 Serial.print(sw4_uS);
 Serial.print("  ");
 Serial.print(sw5_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
   AI_Raw_A3 = analogRead(potPin_A3); // Thumbwheel Pot 3
   
 // Map analog inputs to PPM rates for each of the channels
 //  compensate for analog 0-1023 vs expected 750-1700
   A1_uS = AI_Raw_A1 * adjustRng + pulseMin;
   A2_uS = AI_Raw_A2 * adjustRng + pulseMin;
   A3_uS = AI_Raw_A3 * adjustRng + pulseMin;

 // Check limits
  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 (A3_uS <= pulseMin) A3_uS = pulseMin;   // Min
  if (A3_uS >= pulseMax) A3_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) { // 3-way Switch 2
           sw2_uS = pulseMin;
  } else {
           if (digitalRead(swPin_D4) != 1 ) {
            sw2_uS = pulseMax;
  }        else {
            sw2_uS = pulseMid;
            }
  }
  if (digitalRead(swPin_D5) != 1) { // 3-way Switch 3  
           sw3_uS = pulseMin;
  } else {
          if (digitalRead(swPin_D6) != 1) {   
           sw3_uS = pulseMax;
  }       else {
           sw3_uS = pulseMid;
           }
  }
}