STM32 with Arduino API (2/4): sequence and buttons

In this setup, the button we will use is connected to pin PC5. It is an
active-LOW button: when it is pressed, digitalRead(PC5) returns LOW;
when it is not pressed, it returns HIGH.

The program uses three RGB outputs on the board. First it prepares them in
setup(). Then, in loop(), it chooses the wait time according to the button
state.

#include <Arduino.h>

const int LEDS[] = {PA8, PA9, PA10};
const int TOTAL_LEDS = 3;
const int BUTTON_1 = PC5;  // Active LOW: pressed == LOW

void turnOffAll() {
  for (int i = 0; i < TOTAL_LEDS; i++) {
    analogWrite(LEDS[i], 0);
  }
}

void setup() {
  pinMode(BUTTON_1, INPUT);
  for (int i = 0; i < TOTAL_LEDS; i++) {
    pinMode(LEDS[i], OUTPUT);
  }
}

void loop() {
  bool pressed = digitalRead(BUTTON_1) == LOW;
  int waitTime = pressed ? 150 : 500;

  for (int i = 0; i < TOTAL_LEDS; i++) {
    turnOffAll();
    analogWrite(LEDS[i], 180);
    delay(waitTime);
  }
}

Fill in the table after uploading the program and testing the button. Use only
two rows and leave the others blank if Teach shows more:

- Row 1: button not pressed.
- Row 2: button pressed.
- In Expected digitalRead value, write HIGH or LOW according to the
active-LOW logic.
- In Wait used, record the value the program applies in that case.
- In Brief explanation, connect the button state with the observed speed.

Choose one small modification:

- Change the speed of fast mode.
- Change the speed of normal mode.
- Turn on two colors at once in part of the sequence.
- Invert the logic so the button makes the sequence slower.