💾 ماموریت ۹۴: ذخیره‌ی تنظیمات در حافظه‌ی فلش

سیم‌کشی

1. ESP32 DevKit (D4) ⟷ مقاومت 220Ω (PIN1)
2. مقاومت 220Ω (PIN2) ⟷ LED زرد (ANODE)
3. LED زرد (CATHODE) ⟷ ESP32 DevKit (GND1)

کد

// ESP32 + LittleFS: remember the LED brightness after a reset
// Type a number 0..255 in the Serial Monitor; it is saved to /settings.txt
#include <LittleFS.h>

const int LED = 4;
int level = 128;

void saveLevel() {
  File f = LittleFS.open("/settings.txt", "w");
  f.println(level);
  f.close();
  Serial.println("saved");
}

void setup() {
  Serial.begin(115200);
  LittleFS.begin(true);   // true = format the first time
  if (LittleFS.exists("/settings.txt")) {
    File f = LittleFS.open("/settings.txt", "r");
    level = f.parseInt();
    f.close();
    Serial.print("loaded level ");
    Serial.println(level);
  }
  ledcAttach(LED, 5000, 8);
  ledcWrite(LED, level);
}

void loop() {
  if (Serial.available()) {
    String line = Serial.readStringUntil('\n');
    level = constrain(line.toInt(), 0, 255);
    ledcWrite(LED, level);
    saveLevel();
  }
}