Basic Si5351 VFO for LCD

Si5351_LCD_VFO.ino

/*
Si5351 VFO

By LA3PNA  27 March 2015

This version uses the new version of the Si5351 library from NT7S.
see: http://arduino.cc/en/Reference/AttachInterrupt for what pins that have interrupts.

UNO and 328 boards: Encoder on pin 2 and 3. Center pin to GND.
Leonardo: Encoder on pin 0 and 1. Center pin to GND.

100nF from each of the encoder pins to gnd is used to debounce

The pushbutton goes to pin 4 to set the tuning rate.
Pin 5 is the RX/TX pin. Put this pin LOW for RX, open or high for TX.
Single transistor switch to +RX will work.

VFO will NOT tune in TX.

LCD connections:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 10
 * LCD D5 pin to digital pin 9
 * LCD D6 pin to digital pin 8
 * LCD D7 pin to digital pin 7
 * LCD R/W pin to ground
 * LCD VSS pin to ground
 * LCD VCC pin to 5V
 * 10K pot:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 
 IF frequency is positive for sum product (IF = RF + LO) and negative for diff (IF = RF - LO)
VFO signal output on CLK0, BFO signal on CLK2

ToDo:
*
*/




volatile unsigned long frequency = 7100000; // This will be the frequency it always starts on.
long iffreq = 0; // set the IF frequency in Hz.
long freqstep[] = {50, 100, 500, 1000, 5000, 10000}; // set this to your wanted tuning rate in Hz.
int corr = 10; // this is the correction factor for the Si5351, use calibration sketch to find value.

unsigned int lastReportedPos = 1;   // change management
static boolean rotating = false;    // debounce management

#include <si5351.h>
#include "Wire.h"
#include <LiquidCrystal.h>
Si5351 si5351;
// interrupt service routine vars
boolean A_set = false;
boolean B_set = false;

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega16U4__)
int encoderPinA = 0;   // rigth
int encoderPinB = 1;   // left
#endif
#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
int encoderPinA = 2;   // rigth
int encoderPinB = 3;   // left
#endif
int inData;
bool tx;
int txpin = 5;
int freqsteps = 1;
int stepbutton = 4;
#define arraylength       (sizeof(freqstep) / sizeof(freqstep[0]))


void setup() {

  pinMode(encoderPinA, INPUT);
  pinMode(encoderPinB, INPUT);
  //pinMode(clearButton, INPUT);
  pinMode(stepbutton, INPUT);
  pinMode(txpin, INPUT);
  digitalWrite(txpin, HIGH);
  // turn on pullup resistors
  digitalWrite(encoderPinA, HIGH);
  digitalWrite(encoderPinB, HIGH);
  digitalWrite(stepbutton, HIGH);
#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega16U4__)
  //Code in here will only be compiled if an Arduino Leonardo is used.
  // encoder pin on interrupt 0 (pin 0)
  attachInterrupt(1, doEncoderA, CHANGE);
  // encoder pin on interrupt 1 (pin 1)
  attachInterrupt(0, doEncoderB, CHANGE);
#endif
#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
  //Code in here will only be compiled if an Arduino Uno (or older) is used.
  attachInterrupt(0, doEncoderA, CHANGE);
  // encoder pin on interrupt 1 (pin 1)
  attachInterrupt(1, doEncoderB, CHANGE);
#endif
  si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0);
  si5351.set_correction(corr);
  lcd.begin(16, 2);
  lcd.print("Si5351 VFO");
  Serial.begin(9600);
  delay(2000);
  si5351.set_freq(iffreq * 100ULL, 0, SI5351_CLK2);

}

// main loop, work is done by interrupt service routines, this one only prints stuff
void loop() {
  tx = digitalRead(txpin);
  rotating = true;  // reset the debouncer
  if ( lastReportedPos != frequency) {
    lastReportedPos = frequency;
    lcd.setCursor(0, 1);
    lcd.print(" ");
    lcd.print(frequency);
    si5351.set_freq((frequency + iffreq) * 100ULL, 0, SI5351_CLK0);
  }
  delay(50);

  if (Serial.available() > 0)   // see if incoming serial data:
  {
    inData = Serial.read();  // read oldest byte in serial buffer:
  }
  if (inData == 'F') {
    frequency = Serial.parseInt();
    inData = 0;
  }
  if (digitalRead(stepbutton) == LOW ) {
    delay(150);   // delay to debounce
    if (digitalRead(stepbutton) == LOW ) {
      freqsteps = freqsteps + 1;
      Serial.print(freqstep[freqsteps - 1]);
      Serial.print("     ");
      Serial.print(freqsteps);
      Serial.print("      ");
      Serial.println(sizeof(freqstep));
      if (freqsteps > arraylength - 1 ) {
        freqsteps = 0;
      }
      delay(1000); //delay to avoid many steps at one
    }
  }

}


// Interrupt on A changing state
void doEncoderA() {
  // debounce
  if ( rotating ) delay (1);  // wait a little until the bouncing is done
  // Test transition, did things really change?
  if ( digitalRead(encoderPinA) != A_set ) { // debounce once more
    A_set = !A_set;
    // adjust counter + if A leads B
    if ( A_set && !B_set ) {
      if (!tx) {
        frequency += freqstep[freqsteps]; // hehre is the amount to increase the freq
      }
      rotating = false;  // no more debouncing until loop() hits again
    }
  }
}

// Interrupt on B changing state, same as A above
void doEncoderB() {
  if ( rotating ) delay (1);
  if ( digitalRead(encoderPinB) != B_set ) {
    B_set = !B_set;
    //  adjust counter - 1 if B leads A
    if ( B_set && !A_set ) {
      if (!tx) {
        frequency -= freqstep[freqsteps]; // here is the amount to decrease the freq
      }
      rotating = false;
    }
  }
}