volatile int state = 1;
const int buttonPin = A1;
unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 100;

void setup() {
  Serial.begin(115200);

  GPIOB->MODER = 0x5555;

  GPIOA->MODER = 0x0000;

  analogReadResolution(12);

  attachInterrupt(digitalPinToInterrupt(buttonPin), buttonInterruptHandler, RISING);
}

void updateLEDMeter(int value) {
  int ledsOn = (value + 31) / 32;
  int ledPattern = (1 << ledsOn) - 1;
  GPIOB->ODR = (GPIOB->ODR & ~0xFF) | ledPattern;
}

int led_toggle = 0;

void loop() {
  int value = analogRead(A0) >> 4;
  Serial.println(value);

  if (state == 1) {
    updateLEDMeter(value);
  } else {
    GPIOB->ODR &= ~0xFF;
  }

  delay(10);
}

void buttonInterruptHandler() {
  unsigned long currentTime = millis();
  
  if ((currentTime - lastDebounceTime) > debounceDelay) {
    state = (state == 1) ? 0 : 1;
    lastDebounceTime = currentTime;
  }
}