DIY Arduino VFO with AD9850 & TM1638 Pure Sine Wave Signal Generator for HF Radio

1// by mircemk Mar.2026
2
3#include <TM1638lite.h>
4
5TM1638lite module(4, 3, 2); 
6
7#define W_CLK 8
8#define FQ_UD 9
9#define DATA 10
10#define RESET 11
11#define ENC_A A0
12#define ENC_B A1
13#define ENC_SW A2 // Копчето на енкодерот
14
15unsigned long freq = 7000000; 
16unsigned long steps[] = {10, 100, 1000, 10000, 100000, 1000000};
17int stepIndex = 2; 
18const char* modes[] = {"A       ", "USB     ", "LSB     "};
19int modeIndex = 0;
20long offset = 0; 
21bool offsetActive = false;
22
23// Brightness контроли
24int brightnessPercent = 50; // Почетна на 50%
25bool brightnessMode = false;
26
27unsigned long tempDisplayTimer = 0;
28bool showingTemp = false;
29
30const byte segmentMap[] = { 0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F };
31
32void setup() {
33  pinMode(W_CLK, OUTPUT); pinMode(FQ_UD, OUTPUT);
34  pinMode(DATA, OUTPUT);  pinMode(RESET, OUTPUT);
35  pinMode(ENC_A, INPUT_PULLUP); 
36  pinMode(ENC_B, INPUT_PULLUP);
37  pinMode(ENC_SW, INPUT_PULLUP);
38  
39  ad9850_reset();
40  updateDDS(freq + offset);
41  setBrightnessLevel(brightnessPercent);
42  updateMainDisplay();
43}
44
45void loop() {
46  // Читање на копчето на енкодерот (A3)
47  if (digitalRead(ENC_SW) == LOW) {
48    brightnessMode = !brightnessMode;
49    if (brightnessMode) showTempMsg("BRIGHT  ");
50    else updateMainDisplay();
51    delay(300); // Debounce
52  }
53
54  uint8_t buttons = module.readButtons();
55
56  // Додека сме во Brightness Mode, другите тастери се деактивирани
57  if (!brightnessMode) {
58    if (buttons == 1) { 
59      stepIndex = (stepIndex + 1) % 6;
60      char buffer[9];
61      sprintf(buffer, "S%7ld", steps[stepIndex]); 
62      showTempMsg(buffer);
63      while(module.readButtons() == 1); 
64    }
65    if (buttons == 2) {
66      modeIndex = (modeIndex + 1) % 3;
67      showTempMsg(modes[modeIndex]);
68      while(module.readButtons() == 2);
69    }
70    if (buttons == 4)   setBand(1800000, 2); 
71    if (buttons == 8)   setBand(3500000, 3); 
72    if (buttons == 16)  setBand(7000000, 4); 
73    if (buttons == 32)  setBand(14000000, 5); 
74    if (buttons == 64)  setBand(21000000, 6); 
75
76    if (buttons == 128) {
77      offsetActive = !offsetActive;
78      offset = offsetActive ? 455000 : 0;
79      showTempMsg(offsetActive ? "_455_   " : "OFF     ");
80      module.setLED(7, offsetActive ? 1 : 0); 
81      updateDDS(freq + offset);
82      while(module.readButtons() == 128);
83    }
84  }
85
86  // Енкодер логика (за Фреквенција или за Brightness)
87  static int lastA = HIGH;
88  int currentA = digitalRead(ENC_A);
89  if (currentA != lastA && currentA == LOW) {
90    if (brightnessMode) {
91      // Менување на осветленост (чекор по 10%)
92      if (digitalRead(ENC_B) == LOW) brightnessPercent -= 10;
93      else brightnessPercent += 10;
94      brightnessPercent = constrain(brightnessPercent, 0, 100);
95      
96      setBrightnessLevel(brightnessPercent);
97      char brBuf[9];
98      sprintf(brBuf, "BR  %3d ", brightnessPercent);
99      module.displayText(brBuf);
100    } else {
101      // Стандардна фреквенција
102      if (digitalRead(ENC_B) == LOW) freq -= steps[stepIndex];
103      else freq += steps[stepIndex];
104      freq = constrain(freq, 0, 49999999);
105      updateDDS(freq + offset);
106      if (!showingTemp) updateMainDisplay();
107    }
108  }
109  lastA = currentA;
110
111  if (showingTemp && (millis() > tempDisplayTimer) && !brightnessMode) {
112    showingTemp = false;
113    updateMainDisplay();
114  }
115}
116
117void showTempMsg(const char* msg) {
118  module.displayText(msg);
119  tempDisplayTimer = millis() + 1000;
120  showingTemp = true;
121}
122
123void setBrightnessLevel(int percent) {
124  // TM1638 користи 0x88 (минимум) до 0x8F (максимум) за осветленост
125  byte level = map(percent, 0, 100, 0, 7);
126  digitalWrite(4, LOW); // STB
127  shiftOut(2, 3, LSBFIRST, 0x88 + level); 
128  digitalWrite(4, HIGH); // STB
129}
130
131void updateMainDisplay() {
132  unsigned long tempFreq = freq;
133  for (int i = 7; i >= 0; i--) {
134    byte segs = 0;
135    if (tempFreq > 0 || i == 7) { 
136      segs = segmentMap[tempFreq % 10];
137      tempFreq /= 10;
138    } else {
139      segs = 0x00; 
140    }
141    if (i == 1 || i == 4) segs |= 0x80; 
142    sendRawData(i, segs);
143  }
144}
145
146void sendRawData(byte position, byte data) {
147  digitalWrite(4, LOW);
148  shiftOut(2, 3, LSBFIRST, 0xC0 + (position * 2));
149  shiftOut(2, 3, LSBFIRST, data);
150  digitalWrite(4, HIGH);
151}
152
153void setBand(unsigned long f, int ledIndex) {
154  freq = f;
155  for (int i = 0; i < 7; i++) module.setLED(i, 0); 
156  module.setLED(ledIndex, 1); 
157  updateDDS(freq + offset);
158  updateMainDisplay();
159}
160
161void ad9850_reset() {
162  digitalWrite(W_CLK, LOW); digitalWrite(FQ_UD, LOW);
163  digitalWrite(RESET, LOW); digitalWrite(RESET, HIGH); digitalWrite(RESET, LOW);
164}
165
166void updateDDS(unsigned long f) {
167  unsigned long tuning_word = f * 4294967296ULL / 125000000;
168  for (int i = 0; i < 32; i++) {
169    digitalWrite(DATA, tuning_word & 0x01);
170    digitalWrite(W_CLK, HIGH); digitalWrite(W_CLK, LOW);
171    tuning_word >>= 1;
172  }
173  for (int i = 0; i < 8; i++) {
174    digitalWrite(DATA, LOW);
175    digitalWrite(W_CLK, HIGH); digitalWrite(W_CLK, LOW);
176  }
177  digitalWrite(FQ_UD, HIGH); digitalWrite(FQ_UD, LOW);
178}