/**
 * Simple rotary encoder tuned, I2C SSD1306, AD9850
 * Full 3-digit parsing. 1 MHz to 50 MHz
 * V 1.0.0 ND6T 23 December 2017
 * This source file is under General Public License version 3.0
 *  
 * Pin Connections:      
 *      Display: SDA = A4, SCL = A5
 *      Encoder: A = D2, B = D3, switch = D4
 *      AD9850:CLK = D9, FU = D10, DAT = D11, RST = D12 
 */
#include <Rotary.h>  //Available at:https://github.com/brianlow/Rotary
#include <Adafruit_SSD1306.h>
#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);

  Rotary r = Rotary(2,3);//Encoder to pins 2,3
  unsigned char result;  //ISR results 
  int ind = 4;           //Tuning position indicator
  int oldind=4;          //Previous tuning indicator
  int x;                 //General purpose variable
  long incr = 1000;      //Initial tuning increment
  float ref = 124997110; //My ref clock 
  long upperLimit = 50e6;//Upper frequency limit
  long lowerLimit = 1e6; //Lower frequency limit		
  long freq;             //DDS programming variable
  long oldFQ;            //Frequency change reference
  long FQ = 7.2e6;       //Starting frequency 
  
//Prep for AD9850 
#define CLK 9   //  clock pin
#define FU 10    // freq update pin
#define DAT 11   // DATA pin
#define RST 12   // Reset pin
#define pulse(pin) {digitalWrite(pin, HIGH); digitalWrite(pin, LOW); }
  
void setup(){
  PCICR |= (1 << PCIE2);//Interrupt setup
  PCMSK2 |= (1 << PCINT18) | (1 << PCINT19);//Matrix "state machine" decode
  r.begin();   //Users that downloaded Rotary library before Dec.2018 should delete this line
  
  display.begin(0x3C);  // initialize with the OLED I2C addr
    
  pinMode(CLK, OUTPUT);
  pinMode(FU, OUTPUT);
  pinMode(DAT, OUTPUT);
  pinMode(RST, OUTPUT); 
  pulse(RST);
  pulse(CLK);
  pulse(FU);  // Enables AD9850 serial mode
  pinMode(4,INPUT_PULLUP);//Tuning increment switch
  
 ////////////Splash///////////
  display.clearDisplay(); 
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.print("EZoled    v 1.0.0");
  display.display();
  delay(2000);
  }

void loop(){   
 ind=int((log10(FQ)))-(log10(incr))+2;//Calculate indicator position
   if(FQ<1e7&&FQ>(1e7-13))ind=int((log10(FQ)))-(log10(incr))+1;//Math patch 
   if(incr>100)ind-=1;       //Compensate for decimal places
   if(incr>100000)ind-=1;
   if(ind<0)incr=1000000;
   if(oldind!=ind)show();    //Display if cursor is to be moved
   oldind=ind;  

 if(FQ!=oldFQ){ //If frequency changed then reprogram
  oldFQ=FQ; //Reset reference
  program(); //Re-program the DDS
 }   
}
//*****************FUNCTIONS (subroutines)************************************    
void show() {  //OLED display
  int mhz=(FQ/1e6);                //Truncate MHz
  long khz=FQ-(mhz*1000000);
  if(khz==(-1)){khz=999999;        //Math patch 
  mhz=mhz-1;}                     
  if(khz==(-2)){khz=999998;        //Math patch
  mhz=mhz-1;}
  display.clearDisplay(); 
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.print(mhz);                  //Parse at each 3 digits for easy reading
  display.print(".");
  if((khz/1e3)<10) display.print("0"); //Insert leading zeros if necessary
  if((khz/1e3)<100) display.print("0");
  display.print((khz)/1e3,3);          //Parse final 6 digits
    
  display.setTextSize(2);
  display.setCursor(ind*12,9);
  display.print("-");
  display.display();  
 }

void program() {  //Program the AD9850
  freq=FQ*pow(2,32)/ref; 
  for(x=0;x<4;x++,freq >>=8)shiftOut(DAT,CLK,LSBFIRST,freq);
  shiftOut(DAT,CLK,LSBFIRST,0); 
  pulse(FU);
  show();   
  }

ISR(PCINT2_vect) {                  //Interrupt service routine
  result = r.process();
  if(digitalRead(4)==HIGH){         //If tuning knob is not pressed 
   if(result == DIR_CW){
     FQ+=incr;                      //Clockwise. Add the increment
     if(FQ>upperLimit)FQ=upperLimit;//Unless it exceeds upper limit
  }
  if(result == DIR_CCW){
    FQ-=incr;                       //CounterClockwise subtract it.
    if(FQ<lowerLimit)FQ=lowerLimit; //Unless it is less than lower limit             
    }
  }
  else{     //If the tuning knob is pressed then move the cursor
    if(result == DIR_CW){ //Move cursor right
      incr=incr/10;
        if(incr<1)incr=1; //Lower limit
    }
    if(result == DIR_CCW){ //Move cursor left
      incr=incr*10;
        if((log10(incr))>(log10(FQ)))incr=incr/10;//Upper limit
    }           
   }
  }