M5Core2_PWM.cpp

M5Core2_PWM.cpp

/*
  Wiring Diagram:

      M5Stack Core2
      -------------
      GPIO 26 ---+ 1kΩ Resistor --- Gate/Base of MOSFET/Transistor
                 |
                 GND (Common Ground)

      Motor Supply
      -------------
      +5V --- Anode of Fly-back Diode --- Emitter/Collector of MOSFET/Transistor
      | --- Cathode of Fly-back Diode --- Motor Terminal 1
      GND (Common Ground) --- Motor Terminal 2

      Note: Ensure the M5Stack Core2's GND and the Motor Supply GND are connected.
            The fly-back diode should be across the motor terminals, protecting against inductive spikes.
*/

#include <M5Core2.h>

// --- Hardware Constants ---
constexpr uint8_t PWM_PIN = 26;       // GPIO pin for PWM output
constexpr uint8_t PWM_CHANNEL = 0;      // LEDC channel for PWM
constexpr uint32_t PWM_FREQUENCY = 1000; // PWM frequency in Hz (1 kHz)
constexpr uint8_t PWM_RESOLUTION_BITS = 8; // PWM resolution in bits (0-255)
constexpr uint32_t PWM_MAX_DUTY_CYCLE = (1 << PWM_RESOLUTION_BITS) - 1; // Max duty cycle value (255)

// --- UI Elements ---
M5::Slider *speed_slider = nullptr;
M5::Label *speed_label = nullptr;
M5::Button *start_button = nullptr;
M5::Button *stop_button = nullptr;
M5::Label *fps_label = nullptr;

// --- Global Variables ---
uint8_t current_duty_cycle = 0; // Current PWM duty cycle (0-255)
bool motor_running = false;     // Flag to indicate if the motor is supposed to be running
uint32_t last_update_time_ms = 0; // Time of last FPS update
uint32_t frame_count = 0;       // Frame counter for FPS calculation

/**
 * @brief Updates the FPS (Frames Per Second) display on the screen.
 */
void update_fps() {
    frame_count++;
    uint32_t current_time_ms = millis();
    if (current_time_ms - last_update_time_ms >= 1000) { // Update every 1 second
        float fps = (float)frame_count * 1000.0 / (current_time_ms - last_update_time_ms);
        char fps_text[20];
        snprintf(fps_text, sizeof(fps_text), "FPS: %.1f", fps);
        fps_label->setText(fps_text);
        frame_count = 0;
        last_update_time_ms = current_time_ms;
    }
}

/**
 * @brief Initializes the M5Stack Core2 and the UI elements.
 */
void setup_m5_ui() {
    M5.begin();
    M5.Lcd.setRotation(1); // Set screen orientation
    M5.Lcd.setTextFont(4); // Set default font size (adjust as needed)
    M5.Lcd.setTextColor(TFT_WHITE, TFT_BLACK);

    // Create UI elements
    speed_slider = new M5::Slider(50, 80, 220, 30);
    speed_slider->setRange(0, 100);
    speed_slider->setValue(0);
    speed_slider->setLabel("Speed ( 0–100 % )");

    speed_label = new M5::Label(180, 120, 80, 20, "0 %");

    start_button = new M5::Button(50, 160, 100, 40);
    start_button->setLabel("START");

    stop_button = new M5::Button(170, 160, 100, 40);
    stop_button->setLabel("STOP");

    fps_label = new M5::Label(10, 220, 100, 20, "FPS: 0.0");

    // Add elements to the display stack
    M5.add(speed_slider);
    M5.add(speed_label);
    M5.add(start_button);
    M5.add(stop_button);
    M5.add(fps_label);

    // Set initial state
    current_duty_cycle = 0;
    motor_running = false;
    speed_label->setText("0 %");
}

/**
 * @brief Configures the PWM peripheral for the motor control.
 */
void setup_pwm() {
    // Configure PWM channel
    ledcSetup(PWM_CHANNEL, PWM_FREQUENCY, PWM_RESOLUTION_BITS);
    // Attach PWM channel to the specified GPIO pin
    ledcAttachPin(PWM_PIN, PWM_CHANNEL);
    // Set initial duty cycle to 0 (motor off)
    ledcWrite(PWM_CHANNEL, 0);
}

/**
 * @brief Updates the PWM duty cycle based on the slider value.
 * @param percentage The desired speed percentage (0-100).
 */
void update_motor_duty_cycle(int percentage) {
    // Convert percentage (0-100) to duty cycle (0-255)
    current_duty_cycle = (uint8_t)(((float)percentage / 100.0) * PWM_MAX_DUTY_CYCLE);
    // Apply the new duty cycle if the motor is running
    if (motor_running) {
        ledcWrite(PWM_CHANNEL, current_duty_cycle);
    }
    // Update the display label
    char label_text[10];
    snprintf(label_text, sizeof(label_text), "%d %%", percentage);
    speed_label->setText(label_text);
}

/**
 * @brief Starts the motor with the currently set duty cycle.
 */
void start_motor() {
    motor_running = true;
    ledcWrite(PWM_CHANNEL, current_duty_cycle);
}

/**
 * @brief Stops the motor by setting the duty cycle to 0.
 */
void stop_motor() {
    motor_running = false;
    ledcWrite(PWM_CHANNEL, 0);
}

void setup() {
    setup_m5_ui();
    setup_pwm();

    // Attach event handlers for UI elements
    speed_slider->onChanged([](const Event_t &e) {
        update_motor_duty_cycle(speed_slider->getValue());
    });

    start_button->onPressed([](const Event_t &e) {
        start_motor();
    });

    stop_button->onPressed([](const Event_t &e) {
        stop_motor();
    });

    last_update_time_ms = millis();
    frame_count = 0;
}

void loop() {
    M5.update(); // Update M5Stack screen and button states

    update_fps(); // Update the FPS display

    // No other complex logic needed in the loop for this example,
    // UI updates are handled by M5.update() and event handlers.
}