IF Amplifiers (1st and 2nd)
VFO, BFO Frequencies and AF Amplifier
LPF after RF PA
Receive-Transmit Switching
Microphone Amplifier
RF PA
Arduino Code
#include <LiquidCrystal_I2C.h>
#include <si5351.h>
static const long bandStart = 3500000; // start of VFO range
static const long bandEnd = 3900000; // end of VFO range
static const long bandInit = 3690000; // where to initially set the frequency
volatile long freq = 3690000; // the current freq
volatile long oldfreq = 0; // the previous freq
volatile long LSB_BFO_freq = 10748350; // High side injection thus SB inversion.
volatile long USB_BFO_freq = 10751750; // High side injection thus SB inversion.
volatile long radix = 1000; // How much to change the frequency by, clicking the Up Down switches
volatile long oldradix = 0; // the previous radix
volatile int mode = 0; // the current mode (0=LSB, 1=USB)
volatile int oldmode = 0; // the previous mode (0=LSB, 1=USB)
volatile int TX = 0; // 0=RX, 1=TX
volatile int oldTX = 1; // the old TX
unsigned int encoderA, encoderB, encoderC = 1; // rotary encoder variables
// Rotary encoder pins and other inputs
static const int rotAPin = 2;
static const int rotBPin = 3;
static const int radixPin = 4;
static const int modePin = 5;
static const int PTTPin = 6;
// Instantiate the Objects
LiquidCrystal_I2C lcd(0x3F, 16, 2); // 3F the address of the LCD
Si5351 si5351;
void setup()
{
// Set up I/O pins
pinMode(rotAPin, INPUT);
digitalWrite(rotAPin, HIGH); // internal pull-up enabled
pinMode(rotBPin, INPUT);
digitalWrite(rotBPin, HIGH); // internal pull-up enabled
pinMode(radixPin, INPUT);
digitalWrite(radixPin, HIGH); // internal pull-up enabled
pinMode(modePin, INPUT);
digitalWrite(modePin, HIGH); // internal pull-up enabled
pinMode(PTTPin, INPUT);
digitalWrite(PTTPin, LOW); // internal pull-up disabled
// Initialize the display
lcd.begin();
lcd.backlight();
lcd.noCursor();
// Initialize the DDS
si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0, 62100); // 62100 is the specific calibration factor for this Si5351 board
si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA);
si5351.drive_strength(SI5351_CLK2, SI5351_DRIVE_8MA);
}
void loop()
{
CheckEncoder();
CheckRadixSwitch();
CheckModeSwitch();
CheckPTTPin();
}
void CheckEncoder()
{
byte encoderA = digitalRead(rotAPin);
byte encoderB = digitalRead(rotBPin);
if ((encoderA == HIGH) && (encoderC == LOW))
{
if (encoderB == HIGH)
// Decrease frequency
freq = constrain(freq - radix, bandStart, bandEnd);
else
// Increase frequency
freq = constrain(freq + radix, bandStart, bandEnd);
}
encoderC = encoderA;
if (freq != oldfreq)
{
UpdateDisplay();
SendFrequency();
oldfreq = freq;
}
}
void CheckRadixSwitch()
{
if (digitalRead(radixPin) == 0)
{
radix = radix / 10;
if (radix < 1)
radix = 1000;
delay(200);
}
if (radix != oldradix)
{
UpdateRadixDisplay();
oldradix = radix;
}
}
void CheckModeSwitch()
{
if (digitalRead(modePin) == 0)
mode = 0; // 0=LSB
if (digitalRead(modePin) == 1)
mode = 1; // 1=USB
if (mode != oldmode)
{
UpdateDisplay();
SendFrequency();
oldmode = mode;
}
}
void CheckPTTPin()
{
TX = digitalRead(PTTPin);
if (TX != oldTX)
{
UpdateDisplay();
SendFrequency();
oldTX = TX;
}
}
void UpdateDisplay()
{
// freq
lcd.setCursor(0, 0);
lcd.print(freq);
// mode
lcd.setCursor(0, 1);
if (mode == 0)
lcd.print("LSB");
else
lcd.print("USB");
lcd.setCursor(10, 1);
// PTT
lcd.setCursor(4, 1);
if (TX == 1)
lcd.print("TX");
if (TX == 0)
lcd.print("RX");
// callsign
lcd.setCursor(10, 1);
lcd.print("ZL2CTM");
}
void UpdateRadixDisplay()
{
// radix
if (radix == 1000)
{
lcd.setCursor(9, 0);
lcd.print(" ");
lcd.setCursor(9, 0);
lcd.print(radix);
lcd.setCursor(14, 0);
lcd.print("Hz");
}
if (radix == 100)
{
lcd.setCursor(9, 0);
lcd.print(" ");
lcd.setCursor(10, 0);
lcd.print(radix);
lcd.setCursor(14, 0);
lcd.print("Hz");
}
if (radix == 10)
{
lcd.setCursor(9, 0);
lcd.print(" ");
lcd.setCursor(11, 0);
lcd.print(radix);
lcd.setCursor(14, 0);
lcd.print("Hz");
}
if (radix == 1)
{
lcd.setCursor(9, 0);
lcd.print(" ");
lcd.setCursor(12, 0);
lcd.print(radix);
lcd.setCursor(14, 0);
lcd.print("Hz");
}
}
void SendFrequency()
{
if (mode == 0) // LSB
{
if (TX == 1) // Transmit
{
si5351.set_freq(((LSB_BFO_freq + freq) * 100ULL), SI5351_CLK2); // VFO
si5351.set_freq((LSB_BFO_freq * 100ULL), SI5351_CLK0); // BFO
}
else // Receive
{
si5351.set_freq(((LSB_BFO_freq + freq) * 100ULL), SI5351_CLK0); // VFO
si5351.set_freq((LSB_BFO_freq * 100ULL), SI5351_CLK2); // BFO
}
}
if (mode == 1) // USB
{
if (TX == 1) // Transmit
{
si5351.set_freq(((USB_BFO_freq + freq) * 100ULL), SI5351_CLK2); // VFO
si5351.set_freq((USB_BFO_freq * 100ULL), SI5351_CLK0); // BFO
}
else // Receive
{
si5351.set_freq(((USB_BFO_freq + freq) * 100ULL), SI5351_CLK0); // VFO
si5351.set_freq((USB_BFO_freq * 100ULL), SI5351_CLK2); // BFO
}
}
}
