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cdolek/multiplexer.ino

Last active January 23, 2026 19:00
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dad multiplexer
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multiplexer.ino
/*
PMDG 737 Overhead - Pin & Mux Finder
Finds which standard pin or mux (74HC4067/CD74HC4067) channel changes when you flip a switch.
Assumptions:
- Using Arduino Mega (pins 2-53 exist).
- Mux address pins S0..S3 drive all mux boards in parallel.
- Each mux board has its own SIG line wired to one Arduino analog pin in sigPins[].
- EN on every mux is tied LOW (enabled).
- Switches connect channel -> GND (so INPUT_PULLUP works, LOW = ON).
*/
// ===== DEVICE SELECTION =====
// Device 1: S0-S3 on pins 2,3,4,5
// Device 2: S0-S3 on pins 29,30,31,32
// Set via Serial at startup, or change default here:
uint8_t activeDevice = 2; // Default to Device 2 (send '1' via Serial to switch)
// Device 1 pins
const uint8_t D1_S0 = 2;
const uint8_t D1_S1 = 3;
const uint8_t D1_S2 = 4;
const uint8_t D1_S3 = 5;
// Device 2 pins
const uint8_t D2_S0 = 29;
const uint8_t D2_S1 = 30;
const uint8_t D2_S2 = 31;
const uint8_t D2_S3 = 32;
// Active pins (set after device selection)
uint8_t S0, S1, S2, S3;
const uint8_t sigPins[] = {A0, A1, A2, A3, A4, A5, A6, A7};
const uint8_t numMux = sizeof(sigPins) / sizeof(sigPins[0]);
bool lastMuxState[numMux][16];
bool lastPinState[54];
// DEBUG: Print full state every N milliseconds (set to 0 to disable)
const unsigned long DEBUG_INTERVAL_MS = 5000;
unsigned long lastDebugPrint = 0;
static inline void setMuxChannel(uint8_t ch) {
digitalWrite(S0, (ch >> 0) & 0x01);
digitalWrite(S1, (ch >> 1) & 0x01);
digitalWrite(S2, (ch >> 2) & 0x01);
digitalWrite(S3, (ch >> 3) & 0x01);
delayMicroseconds(50); // settle time
}
static inline void printP3(int n) {
Serial.print("P");
if (n < 100) Serial.print("0");
if (n < 10) Serial.print("0");
Serial.print(n);
}
void selectDevice(uint8_t device) {
activeDevice = device;
if (device == 1) {
S0 = D1_S0; S1 = D1_S1; S2 = D1_S2; S3 = D1_S3;
Serial.println("Device 1 selected (pins 2,3,4,5)");
} else {
S0 = D2_S0; S1 = D2_S1; S2 = D2_S2; S3 = D2_S3;
Serial.println("Device 2 selected (pins 29,30,31,32)");
}
}
void directPinTest() {
// Direct test: read A0-A7 without mux logic
Serial.println("\n--- DIRECT PIN TEST (A0-A7) ---");
Serial.println("Short each pin to GND with a wire to verify.");
for (uint8_t idx = 0; idx < 8; idx++) {
uint8_t pin = A0 + idx;
pinMode(pin, INPUT_PULLUP);
delay(5);
bool state = digitalRead(pin);
Serial.print("A");
Serial.print(idx);
Serial.print(": ");
Serial.println(state == LOW ? "LOW (connected to GND)" : "HIGH (floating/open)");
}
Serial.println("--- END DIRECT TEST ---");
Serial.println("If all show HIGH, short A0 to GND and send 'T' again.\n");
}
bool isMuxAddressPin(uint8_t pin) {
// Skip address pins for BOTH devices to avoid conflicts
return (pin >= 2 && pin <= 5) || (pin >= 29 && pin <= 32);
}
void initializePins() {
// Mux address pins
pinMode(S0, OUTPUT);
pinMode(S1, OUTPUT);
pinMode(S2, OUTPUT);
pinMode(S3, OUTPUT);
setMuxChannel(0);
// SIG pins
for (uint8_t m = 0; m < numMux; m++) {
pinMode(sigPins[m], INPUT_PULLUP);
}
// Standard pins as INPUT_PULLUP (skip mux address pins for both devices)
for (uint8_t i = 2; i < 54; i++) {
if (isMuxAddressPin(i)) continue;
pinMode(i, INPUT_PULLUP);
lastPinState[i] = digitalRead(i);
}
// Initialize mux states
delay(10);
for (uint8_t ch = 0; ch < 16; ch++) {
setMuxChannel(ch);
for (uint8_t m = 0; m < numMux; m++) {
(void)digitalRead(sigPins[m]);
lastMuxState[m][ch] = digitalRead(sigPins[m]);
}
}
}
void setup() {
Serial.begin(115200);
Serial.println("\n--- PMDG 737 PIN/MUX TARAYICI ---");
Serial.println(" 1 = Device 1 (S0-S3 on pins 2,3,4,5)");
Serial.println(" 2 = Device 2 (S0-S3 on pins 29,30,31,32)");
Serial.println(" T = Direct A0-A7 test (bypass mux)");
Serial.println("Send '1', '2', or 'T' via Serial.\n");
// Use default device
selectDevice(activeDevice);
initializePins();
Serial.println("Baslangic durumu okundu. Hazir.");
Serial.println("Lutfen bir switch'i hareket ettirin...\n");
}
void loop() {
// Check for device switch command via Serial
if (Serial.available() > 0) {
char c = Serial.read();
if (c == '1' && activeDevice != 1) {
selectDevice(1);
initializePins();
Serial.println("Switched to Device 1. Ready.\n");
} else if (c == '2' && activeDevice != 2) {
selectDevice(2);
initializePins();
Serial.println("Switched to Device 2. Ready.\n");
} else if (c == 'T' || c == 't') {
directPinTest();
}
}
// DEBUG: Periodically dump all mux states to verify wiring
if (DEBUG_INTERVAL_MS > 0 && (millis() - lastDebugPrint >= DEBUG_INTERVAL_MS)) {
lastDebugPrint = millis();
Serial.println("\n--- DEBUG: MUX STATE DUMP ---");
for (uint8_t m = 0; m < numMux; m++) {
Serial.print("Mux ");
Serial.print(m);
Serial.print(" (A");
Serial.print(sigPins[m] - A0);
Serial.print("): ");
for (uint8_t ch = 0; ch < 16; ch++) {
setMuxChannel(ch);
delayMicroseconds(50);
bool state = digitalRead(sigPins[m]);
Serial.print(state == LOW ? "1" : "0"); // 1 = ON (LOW), 0 = OFF (HIGH)
}
Serial.println();
}
Serial.println("(1=LOW/ON, 0=HIGH/OFF)");
Serial.println("--- END DEBUG ---\n");
}
// 1) Scan standard pins
for (uint8_t i = 2; i < 54; i++) {
if (isMuxAddressPin(i)) continue;
bool currentState = digitalRead(i);
if (currentState != lastPinState[i]) {
Serial.print("STANDART PIN DEGISTI -> Pin: ");
Serial.print(i);
Serial.println(currentState == LOW ? " (BASILDI / ON)" : " (BIRAKILDI / OFF)");
lastPinState[i] = currentState;
delay(30);
}
}
// 2) Scan mux channels
for (uint8_t ch = 0; ch < 16; ch++) {
setMuxChannel(ch);
for (uint8_t m = 0; m < numMux; m++) {
(void)digitalRead(sigPins[m]); // optional glitch flush
bool currentState = digitalRead(sigPins[m]);
if (currentState != lastMuxState[m][ch]) {
int totalID = (m * 16) + ch;
Serial.print("MUX TESPIT EDILDI -> Mux No: ");
Serial.print(m);
Serial.print(" | Kanal: ");
Serial.print(ch);
Serial.print(" | ESKI LUA KODU: ");
printP3(totalID);
Serial.println(currentState == LOW ? " (ON)" : " (OFF)");
lastMuxState[m][ch] = currentState;
delay(30);
}
}
}
}
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