/* 
 * A simple single freq AD9850 Arduino test script
 * Original AD9851 DDS sketch by Andrew Smallbone at www.rocketnumbernine.com
 * Modified for testing the inexpensive AD9850 ebay DDS modules
 * Pictures and pinouts at nr8o.dhlpilotcentral.com
 * 9850 datasheet at http://www.analog.com/static/imported-files/data_sheets/AD9850.pdf
 * Use freely
 */

#include <U8glib.h>

// Uncomment just one of the following:
   #define BAND40 //Remove comment markers to scan for 40 mtrs
//   #define BAND20 //Remove comment markers to scan for 20 mtrs
//   #define BAND15 //Remove comment markers to scan for 15 mtrs
// Using the above strategy, other bands may be defined as needed
 
 #define W_CLK 8       // Pin 8 - connect to AD9850 module word load clock pin (CLK)
 #define FQ_UD 9       // Pin 9 - connect to freq update pin (FQ)
 #define DATA 10       // Pin 10 - connect to serial data load pin (DATA)
 #define RESET 11      // Pin 11 - connect to reset pin (RST).
 
 #define pulseHigh(pin) {digitalWrite(pin, HIGH); digitalWrite(pin, LOW); }
U8GLIB_SH1106_128X64 u8g(3, 4, 7, 6 , 5); // SW SPI Com: CLK = 3, MOSI = 4, CS = 7, dc = 6, RES = 5
double Start_Freq = 6.4e6; //13.4e6;//  20.5e6;//6.4e6; //start Freq; in Mhz  20.5e6;//  3.6e6;//
double End_Freq =  7.8e6; //14.5e6;// 22.5e6;//7.8e6; //End Scan Freq; in Mhz 22.5e6;// 4.5e6;//
double Step_Freq = 10e3; //Step  Freq; in KHz 25000;// 25e3;// 
double VSWRLim = 1.7;
double current_freq;
int FwdOffSet;
int RevOffSet;
int FwdSCVal = 30;// initialially set to 1; then set to reading found when antenna leg of bridge is shorted; Diode sensitivity compensation
int RevSCVal = 40;// initialially set to 1; then set to reading found when antenna leg of bridge is shorted; Diode sensitivity compensation
int FwdOpAmpGain = 92;// initialially set to 1; then set to FWD reading found when Cathodes of D1 and D2 are shorted together; (Op Amp Gain loop compensation)
int RevOpAmpGain = 88;// initialially set to 1; then set to REV reading found when Cathodes of D1 and D2 are shorted together; (Op Amp Gain loop compensation)
double LastVSWR = 999;
bool VSWRtrendUP = false;
bool Incrmnt = true;
bool RunCurve = true;
char buf [32]; // used to concatenate strings & numerical data for display
double SweepData[8];
// Small signal correction table [array] 
int CrtdVal[] = {
  0, 0, 2, 4, 7, 9, 12, 14, 16, 19, 22, 25, 28, 31, 33, 35,36, 37, 39, 40, 41, 42, 43, 44, 44, 46, 47, 49, 50, 52, 53, 54, 55, 57, 58, 
  59, 60, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 79, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
  98, 99, 100, 101, 102, 103, 104, 105, 105, 106, 107, 108, 109, 110, 111, 111, 112, 113, 114, 114, 115, 116, 117, 117, 118, 119, 120, 120, 121, 122, 122,
  123, 124, 124, 125, 126, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 139, 140, 141, 142, 143, 143, 144, 145, 146, 147, 147,
  148, 149, 150, 151, 151, 152, 153, 154, 154, 155, 156, 157, 157, 158, 159, 160, 160, 161, 162, 162, 163, 164, 164, 165, 166, 166, 167, 168, 168, 169, 170,
  171, 172, 172, 173, 174, 175, 176, 176, 177, 178, 179, 179, 180, 181, 182, 182, 183, 184, 185, 185, 186, 187, 187, 188, 189, 190, 190, 191, 192, 193, 193,
  194, 195, 196, 196, 197, 198, 198, 199, 200, 200, 201, 202, 203, 203, 204, 205, 205, 206, 207, 207, 208, 209, 209, 210, 211, 211, 212, 213, 213, 214, 215,
  215, 216, 216, 217, 218, 218, 219, 220, 220, 221, 221, 222, 223, 223, 224, 225, 225, 226, 226, 227, 228, 228, 229, 229, 230, 230, 231, 232, 232, 233, 233,
  234, 234, 235, 235
  };

 // transfers a byte, a bit at a time, LSB first to the 9850 via serial DATA line
void tfr_byte(byte data)
{
  for (int i=0; i<8; i++, data>>=1) {
    digitalWrite(DATA, data & 0x01);
    pulseHigh(W_CLK);   //after each bit sent, CLK is pulsed high
  }
}

 // frequency calc from datasheet page 8 = <sys clock> * <frequency tuning word>/2^32
void sendFrequency(double frequency) {
  int32_t freq = frequency * 4294967295/125000000;  // note 125 MHz clock on 9850
  for (int b=0; b<4; b++, freq>>=8) {
    tfr_byte(freq & 0xFF);
  }
  tfr_byte(0x000);   // Final control byte, all 0 for 9850 chip
  pulseHigh(FQ_UD);  // Done!  Should see output
}

void setup() {
  char str_Band[4];
 // configure arduino data pins for output
  pinMode(FQ_UD, OUTPUT);
  pinMode(W_CLK, OUTPUT);
  pinMode(DATA, OUTPUT);
  pinMode(RESET, OUTPUT);
  #ifdef BAND40 //Set Freq Limits for 40_MTRS 
    Start_Freq = 6.4e6; // Freq; in Mhz
    End_Freq =  7.8e6; // Freq; in Mhz
    sprintf (str_Band, "40"); //str_Band = "40"
  #endif
  #ifdef BAND20 //Set Freq Limits for 20_MTRS 
    Start_Freq = 13.4e6; // Freq; in Mhz  20.5e6;//  3.6e6;//
    End_Freq =  14.8e6; // Freq; in Mhz
    sprintf (str_Band, "20"); //str_Band = "20"
  #endif
  #ifdef BAND15 //Set Freq Limits for 15_MTRS 
    Start_Freq = 20.5e6; // Freq; in Mhz
    End_Freq =  22.5e6; // Freq; in Mhz
    sprintf (str_Band, "15"); //str_Band = "15"
  #endif
  pulseHigh(RESET);
  pulseHigh(W_CLK);
  pulseHigh(FQ_UD);  // this pulse enables serial mode - Datasheet page 12 figure 10
  current_freq = Start_Freq;
  Serial.begin(9600);
  SweepData[1] = 999; //Lowest Recorded VSWR
  SweepData[2] = 0;
  SweepData[3] =0;
  SweepData[4] = 9999; 
  SweepData[5] = 0;
  SweepData[6] = 0;
  char buf2 [32];
  char buf3 [32];
  char buf4 [32];
  char str_StrtFq[6];
  char str_EndFq[6];
  char str_SWRLim[6];
  char str_Step[6];
  double SFqMhz = Start_Freq/1000000;
  double EFqMhz = End_Freq/1000000;
  dtostrf(SFqMhz, 4, 2, str_StrtFq);// char *dtostrf(double val, signed char width, unsigned char prec, char *s)
  dtostrf(EFqMhz, 4, 2, str_EndFq);
  dtostrf(VSWRLim, 4, 2, str_SWRLim);
  dtostrf(Step_Freq/1000, 4, 1, str_Step);
  sprintf (buf,"%s to %s Mhz", str_StrtFq,str_EndFq);
  sprintf (buf2,"MAX VSWR: %s", str_SWRLim);
  sprintf (buf3,"Step: %s Khz", str_Step);
  sprintf (buf4,"%sM Ant Analyzer", str_Band);
  
   u8g.firstPage();
   do {
    int row = 11; //first OLED row to print on
    u8g.setFont(u8g_font_unifont);
    u8g.setPrintPos(0, row);
    u8g.print(buf4);
    row = NuRow(row);
    u8g.setPrintPos(0, row);
    u8g.print(buf);
    row = NuRow(row);
    u8g.setPrintPos(0, row);
    u8g.print(buf2);
    row = NuRow(row);
    u8g.setPrintPos(0, row);
    u8g.print(buf3);
    u8g.setFont(u8g_font_7x13);
    row = NuRow(row);
    u8g.setPrintPos(0, row);
    u8g.print("AD9850; 128x64Disp");
  } while( u8g.nextPage() );
  delay(5500);
 }

void loop() {
  int incomingByte = 0;   // for incoming serial data
  sendFrequency(1.0);  // set AD9850 output to 1 Hz
  delay(100);
  RevOffSet = 0.0;
  FwdOffSet = 0.0;
  for (int i=0; i<20; i++) {
       RevOffSet += analogRead(A0);
       FwdOffSet += analogRead(A1);
       delay(10);
     }
     RevOffSet =RevOffSet/20.0;
     FwdOffSet = FwdOffSet/20.0;
  if (RunCurve){
     RunCurve = PrintNextPoint(RunCurve);
  }

  else{
    sendFrequency(1.0);  // set AD9850 output to 1 Hz
    char buf2 [32];
    char buf3 [32];
    double BestSWR = SweepData[1];
    char str_SWR[6];
    char str_Ohms[6];
    char str_LowFreq[6];
    char str_HiFreq[6];
    dtostrf(BestSWR, 3, 1, str_SWR);
    dtostrf(SweepData[4], 3, 0, str_Ohms);
    sprintf (buf2,"SWR:%s/%s Ohm", str_SWR, str_Ohms);

    dtostrf(SweepData[6]/1000000, 4, 2, str_LowFreq);
    dtostrf(SweepData[5]/1000000, 4, 2, str_HiFreq);
    sprintf (buf3,"L/H %s/%s Mhz", str_LowFreq, str_HiFreq);

    if(SweepData[2]> 0 && SweepData[3] >0){
      double centerFreq = (SweepData[2]+(SweepData[3]-SweepData[2])/2);
      char str_CFq[6];
      double CFqMhz = centerFreq/1000000;
      dtostrf(CFqMhz, 5, 3, str_CFq);// char *dtostrf(double val, signed char width, unsigned char prec, char *s)
      sprintf (buf,"Freq: %sMhz", str_CFq);
    }
    else sprintf (buf,"%s", "NO DATA AVAILABLE!");
    
    u8g.firstPage();
   do {
     int row = 11; //first OLED row to print on
     u8g.setFont(u8g_font_unifont);
     u8g.setPrintPos(0, row);
     u8g.print(buf);
     u8g.setFont(u8g_font_7x13);
     row = NuRow(row);
     u8g.setPrintPos(0, row);
     u8g.print(buf3);
     u8g.setFont(u8g_font_unifont);
     row = NuRow(row);
     u8g.setPrintPos(0, row);
     u8g.print(buf2);
     row = NuRow(row);
     u8g.setPrintPos(0, row);
     u8g.print("Hit 'Reset' Btn");
     row = NuRow(row);
     u8g.setPrintPos(0, row);
     u8g.print("to Scan Again");
    } while( u8g.nextPage() );
    delay(2000);
  }
  
 
}

//*******************************************************//
bool PrintNextPoint(bool RunCurve){
  float FWD;
  float REV;
  double VSWR;
  double EffOhms;
  bool GudRun = false;

  while (RunCurve){
    
    sendFrequency(current_freq);  // freq
    delay(100);
     // Read the forward and reverse voltages
     REV = 0.0;
     FWD = 0.0;
     for (int i=0; i<70; i++) {
       REV += (analogRead(A0)-RevOffSet);
       FWD += (analogRead(A1)-FwdOffSet);
       
     }
     REV = REV/70.0;
     FWD = FWD/70.0;
    //REV = analogRead(A0)-RevOffSet;
    REV = (FwdOpAmpGain*REV)/RevOpAmpGain; // apply Op Amp Gain loop compensation
    REV = CorrectReading(REV);// now using table apply Small Signal correction value
    
    //FWD = analogRead(A1)-FwdOffSet;
    FWD = (RevSCVal*FWD)/FwdSCVal;// apply "Short Circuit" offset
    FWD = CorrectReading(FWD);// now using table apply Small Signal correction value
    if(REV>=FWD){
      // To avoid a divide by zero or negative VSWR then set to max 999
      VSWR = 999;
    }else{
      // Calculate VSWR
      
      VSWR = ((FWD+REV)/(FWD-REV));
    }
    if(FWD>=116) EffOhms = VSWR*47.0;//FWD>=94
    else  EffOhms = 47.0/VSWR;
    u8g.firstPage();
    // Post results
    do {
      int row = 11; //first OLED row to print on
      u8g.setFont(u8g_font_7x13);
      u8g.setPrintPos(0, row);
      u8g.print("Freq: ");
      u8g.print(int(current_freq/1000));
      u8g.print(" KHz");
      if (Incrmnt) u8g.print(" +");
      else u8g.print(" -");
      u8g.setFont(u8g_font_unifont);
      row = NuRow(row);
      u8g.setPrintPos(0, row);
      u8g.print("VSWR: ");
      u8g.print(VSWR);//LastVSWR
      if (VSWRtrendUP) u8g.print(" +");
      else u8g.print(" -");
      if( VSWR > VSWRLim)u8g.print("!!");
       else u8g.print("  ");
      row = NuRow(row);
      u8g.setPrintPos(0, row);
      u8g.print("Ohms: ");
      u8g.print(EffOhms);
      row = NuRow(row);
      u8g.setPrintPos(8, row);  
      u8g.print("Fwd: ");
      u8g.print(FWD);
      row = NuRow(row);
      u8g.setPrintPos(8, row);
      u8g.print("Rev: ");
      u8g.print(REV);
    } while( u8g.nextPage() );
    // Check for & Save interesting data
    if (VSWR < SweepData[1]) {
      if (Incrmnt){
        SweepData[1] = VSWR;
        SweepData[2] = current_freq;
        SweepData[4] = EffOhms;
      }
    }
    if (VSWR == SweepData[1]) {
      if (Incrmnt){
        SweepData[3] = current_freq;
      }
    }
    if (VSWR < LastVSWR-0.06){
      VSWRtrendUP = false;
       LastVSWR = VSWR;
    }

    if (VSWR > LastVSWR+0.06){
      VSWRtrendUP = true;
      LastVSWR = VSWR;
    }
    if( VSWR < VSWRLim) GudRun = true;
    if (Incrmnt && VSWR < VSWRLim ) SweepData[5] = current_freq; // capture Highest Freq that is below the VSWR limit
    if (!Incrmnt && VSWR < VSWRLim ) SweepData[6] = current_freq; // capture Lowest Freq that is below the VSWR limit 
    if (GudRun){
      if (Incrmnt && VSWRtrendUP && VSWR > VSWRLim )Incrmnt = false;
      else if (!Incrmnt && VSWRtrendUP && VSWR > VSWRLim ){
        Incrmnt = true;
        if (GudRun) RunCurve = false;
      }
    }
    if (current_freq >  End_Freq) Incrmnt = false;
    if (current_freq <  Start_Freq) RunCurve = false; // Exit The freqs of interest have been examined; But aparently a usable SWR was not found 
    if (Incrmnt) current_freq += Step_Freq;
    else current_freq -= Step_Freq;
    }// end While Loop
    return RunCurve;
}

double CorrectReading(double ReadVal){
//  Serial.println(ReadVal);
//  if (ReadVal > 263)return ReadVal;// if (ReadVal > 0)return ReadVal;//
//  return CrtdVal[ReadVal];
 if (ReadVal > 70)return 0.8*ReadVal+57;// if (ReadVal > 0)return ReadVal;//
 if (ReadVal < 13)return 3.6*(ReadVal*ReadVal)/15;
 float CalcVal =1.1*( 8+(2.1*ReadVal)-((ReadVal*ReadVal)*10.7/1000));
 return CalcVal;
}

int NuRow(int oldrow){
   {
    int pixcnt = 13;
    oldrow += pixcnt;
    return oldrow; 
   }
}