MaTouch Rotary Display

Matouch-Rotary-Display

The Matouch Rotary Display is a development board for the ESP32-S3 module. It features a nice touchscreen display, a rotary encoder, a push button behind the screen, and some expansion headers along with other peripherals like a micro-SD card.

The espp::MatouchRotaryDisplay component provides a singleton hardware abstraction for initializing the touch, display, and button.

API Reference

Header File

Classes

class MatouchRotaryDisplay : public espp::BaseComponent

The MatouchRotaryDisplay class provides an interface to the MaTouch Rotary Display 1.28” ESP32-S3 development board (Model MTRO128G).

The class provides access to the following features:

  • Touchpad (CST816S)

  • Display (GC9A01)

  • ABI Encoder

For more information see: https://github.com/Makerfabs/MaTouch-ESP32-S3-RotaryIPS-Display1.28-GC9A01

The class is a singleton and can be accessed using the get() method.

Example

  espp::MatouchRotaryDisplay &mt_display = espp::MatouchRotaryDisplay::get();
  mt_display.set_log_level(espp::Logger::Verbosity::INFO);

  auto on_button_pressed = [&](const auto &event) {
    if (event.active) {
      logger.info("Button pressed!");
    } else {
      logger.info("Button released!");
      // clear the screen
      std::lock_guard<std::recursive_mutex> lock(lvgl_mutex);
      clear_circles();
    }
  };

  auto on_touch = [&](const auto &touch) {
    // NOTE: since we're directly using the touchpad data, and not using the
    // TouchpadInput + LVGL, we'll need to ensure the touchpad data is
    // converted into proper screen coordinates instead of simply using the
    // raw values.
    static auto previous_touchpad_data = mt_display.touchpad_convert(touch);
    auto touchpad_data = mt_display.touchpad_convert(touch);
    if (touchpad_data != previous_touchpad_data) {
      logger.info("Touch: {}", touchpad_data);
      previous_touchpad_data = touchpad_data;
      // if there is a touch point, draw a circle
      if (touchpad_data.num_touch_points > 0) {
        std::lock_guard<std::recursive_mutex> lock(lvgl_mutex);
        draw_circle(touchpad_data.x, touchpad_data.y, 10);
      }
    }
    previous_touchpad_data = touchpad_data;
  };

  // initialize the LCD
  if (!mt_display.initialize_lcd()) {
    logger.error("Failed to initialize LCD!");
    return;
  }
  // set the pixel buffer to be 50 lines high
  static constexpr size_t pixel_buffer_size = mt_display.lcd_width() * 50;
  // initialize the LVGL display for the Matouch-Rotary-Display
  if (!mt_display.initialize_display(pixel_buffer_size)) {
    logger.error("Failed to initialize display!");
    return;
  }
  // initialize the touchpad
  if (!mt_display.initialize_touch(on_touch)) {
    logger.error("Failed to initialize touchpad!");
    return;
  }
  // initialize the rotary encoder
  if (!mt_display.initialize_encoder()) {
    logger.error("Failed to initialize rotary encoder!");
    return;
  }
  // initialize the button
  if (!mt_display.initialize_button(on_button_pressed)) {
    logger.error("Failed to initialize button!");
    return;
  }

  // set the background color to black
  lv_obj_t *bg = lv_obj_create(lv_screen_active());
  lv_obj_set_size(bg, mt_display.lcd_width(), mt_display.lcd_height());
  lv_obj_set_style_bg_color(bg, lv_color_make(0, 0, 0), 0);

  // add text in the center of the screen
  lv_obj_t *label = lv_label_create(lv_screen_active());
  lv_label_set_text(label, "Touch the screen!\nPress the button to clear circles.");
  lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);
  lv_obj_set_style_text_align(label, LV_TEXT_ALIGN_CENTER, 0);

  // add a button in the top left which (when pressed) will rotate the display
  // through 0, 90, 180, 270 degrees
  lv_obj_t *btn = lv_btn_create(lv_screen_active());
  lv_obj_set_size(btn, 50, 50);
  lv_obj_align(btn, LV_ALIGN_TOP_MID, 0, 0);
  lv_obj_t *label_btn = lv_label_create(btn);
  lv_label_set_text(label_btn, LV_SYMBOL_REFRESH);
  // center the text in the button
  lv_obj_align(label_btn, LV_ALIGN_CENTER, 0, 0);
  lv_obj_add_event_cb(
      btn,
      [](auto event) {
        std::lock_guard<std::recursive_mutex> lock(lvgl_mutex);
        clear_circles();
        static auto rotation = LV_DISPLAY_ROTATION_0;
        rotation = static_cast<lv_display_rotation_t>((static_cast<int>(rotation) + 1) % 4);
        lv_display_t *disp = lv_display_get_default();
        lv_disp_set_rotation(disp, rotation);
      },
      LV_EVENT_PRESSED, nullptr);

  // disable scrolling on the screen (so that it doesn't behave weirdly when
  // rotated and drawing with your finger)
  lv_obj_set_scrollbar_mode(lv_screen_active(), LV_SCROLLBAR_MODE_OFF);
  lv_obj_clear_flag(lv_screen_active(), LV_OBJ_FLAG_SCROLLABLE);

  // start a simple thread to do the lv_task_handler every 16ms
  espp::Task lv_task({.callback = [](std::mutex &m, std::condition_variable &cv) -> bool {
                        {
                          std::lock_guard<std::recursive_mutex> lock(lvgl_mutex);
                          lv_task_handler();
                        }
                        std::unique_lock<std::mutex> lock(m);
                        cv.wait_for(lock, 16ms);
                        return false;
                      },
                      .task_config = {
                          .name = "lv_task",
                      }});
  lv_task.start();

  // set the display brightness to be 75%
  mt_display.brightness(75.0f);

  while (true) {
    auto start = esp_timer_get_time();
    // get the encoder count and update the label with it
    {
      std::lock_guard<std::recursive_mutex> lock(lvgl_mutex);
      int encoder_count = mt_display.encoder_value();
      lv_label_set_text_fmt(label,
                            "Touch the screen!\nPress the button to clear circles.\nEncoder: %d",
                            encoder_count);
    }
    // sleep for the remaining time
    auto end = esp_timer_get_time();
    auto elapsed = end - start;
    std::this_thread::sleep_for(50ms - std::chrono::microseconds(elapsed));
  }

Public Types

using Pixel = lv_color16_t

Alias for the pixel type used by the Matouch display.

using DisplayDriver = espp::Gc9a01

Alias for the display driver used by the Matouch display.

Public Functions

I2c &internal_i2c()

Get a reference to the internal I2C bus

Note

The internal I2C bus is used for the touchscreen

Returns:

A reference to the internal I2C bus

espp::Interrupt &interrupts()

Get a reference to the interrupts

Returns:

A reference to the interrupts

bool initialize_encoder()

Initialize the encoder

Returns:

true if the encoder was successfully initialized, false otherwise

std::shared_ptr<Encoder> encoder() const

Get the encoder

Returns:

A shared pointer to the encoder

int encoder_value()

Get the encoder value

Returns:

The encoder value

bool initialize_button(const button_callback_t &callback = nullptr)

Initialize the button

Parameters:

callback – The callback function to call when the button is pressed

Returns:

true if the button was successfully initialized, false otherwise

bool button_state() const

Get the button state

Returns:

The button state (true = button pressed, false = button released)

bool initialize_touch(const touch_callback_t &callback = nullptr)

Initialize the touchpad

Note

This will also register an interrupt for the touchpad which will automatically update the touchpad data when the touchpad is touched

Warning

This method should be called after the display has been initialized if you want the touchpad to be recognized and used with LVGL and its objects.

Parameters:

callback – The callback function to call when the touchpad is touched. This callback will be called after the touchpad data has been updated and will be passed the updated touchpad data.

Returns:

true if the touchpad was successfully initialized, false otherwise

std::shared_ptr<TouchpadInput> touchpad_input() const

Get the touchpad input

Returns:

A shared pointer to the touchpad input

TouchpadData touchpad_data() const

Get the most recent touchpad data

Returns:

The touchpad data

void touchpad_read(uint8_t *num_touch_points, uint16_t *x, uint16_t *y, uint8_t *btn_state)

Get the most recent touchpad data

See also

touchpad_data()

Note

This method is a convenience method for integrating with LVGL, the data it returns is identical to the data returned by the touchpad_data() method

Parameters:

  • num_touch_points – The number of touch points

  • x – The x coordinate

  • y – The y coordinate

  • btn_state – The button state (0 = button released, 1 = button pressed)

TouchpadData touchpad_convert(const TouchpadData &data) const

Convert touchpad data from raw reading to display coordinates

Note

Uses the touch_invert_x and touch_invert_y settings to determine if the x and y coordinates should be inverted

Parameters:

data – The touchpad data to convert

Returns:

The converted touchpad data

bool initialize_lcd()

Initialize the LCD (low level display driver)

Returns:

true if the LCD was successfully initialized, false otherwise

bool initialize_display(size_t pixel_buffer_size)

Initialize the display (lvgl display driver)

Note

This will also allocate two full frame buffers in the SPIRAM

Parameters:

pixel_buffer_size – The size of the pixel buffer

Returns:

true if the display was successfully initialized, false otherwise

std::shared_ptr<Display<Pixel>> display() const

Get a shared pointer to the display

Returns:

A shared pointer to the display

void brightness(float brightness)

Set the brightness of the backlight

Note

This function will only work after initialize_lcd() has been called

Parameters:

brightness – The brightness of the backlight as a percentage (0 - 100)

float brightness() const

Get the brightness of the backlight

Note

This function will only work after initialize_lcd() has been called

Returns:

The brightness of the backlight as a percentage (0 - 100)

Pixel *vram0() const

Get the VRAM 0 pointer (DMA memory used by LVGL)

Note

This is the memory used by LVGL for rendering

Note

This is null unless initialize_display() has been called

Returns:

The VRAM 0 pointer

Pixel *vram1() const

Get the VRAM 1 pointer (DMA memory used by LVGL)

Note

This is the memory used by LVGL for rendering

Note

This is null unless initialize_display() has been called

Returns:

The VRAM 1 pointer

uint8_t *frame_buffer0() const

Get the frame buffer 0 pointer

Note

This memory is designed to be used by the application developer and is provided as a convenience. It is not used by the display driver.

Note

This is null unless initialize_display() has been called

Returns:

The frame buffer 0 pointer

uint8_t *frame_buffer1() const

Get the frame buffer 1 pointer

Note

This memory is designed to be used by the application developer and is provided as a convenience. It is not used by the display driver.

Note

This is null unless initialize_display() has been called

Returns:

The frame buffer 1 pointer

void write_command(uint8_t command, std::span<const uint8_t> parameters, uint32_t user_data)

Write command and optional parameters to the LCD

Note

This method is designed to be used by the display driver

Note

This method queues the data to be written to the LCD, only blocking if there is an ongoing SPI transaction

Parameters:

  • command – The command to write

  • parameters – The command parameters to write

  • user_data – User data to pass to the spi transaction callback

void write_lcd_frame(const uint16_t x, const uint16_t y, const uint16_t width, const uint16_t height, uint8_t *data)

Write a frame to the LCD

Note

This method queues the data to be written to the LCD, only blocking if there is an ongoing SPI transaction

Parameters:

  • x – The x coordinate

  • y – The y coordinate

  • width – The width of the frame, in pixels

  • height – The height of the frame, in pixels

  • data – The data to write

void write_lcd_lines(int xs, int ys, int xe, int ye, const uint8_t *data, uint32_t user_data)

Write lines to the LCD

Note

This method queues the data to be written to the LCD, only blocking if there is an ongoing SPI transaction

Parameters:

  • xs – The x start coordinate

  • ys – The y start coordinate

  • xe – The x end coordinate

  • ye – The y end coordinate

  • data – The data to write

  • user_data – User data to pass to the spi transaction callback

inline const std::string &get_name() const

Get the name of the component

Note

This is the tag of the logger

Returns:

A const reference to the name of the component

inline void set_log_tag(const std::string_view &tag)

Set the tag for the logger

Parameters:

tag – The tag to use for the logger

inline espp::Logger::Verbosity get_log_level() const

Get the log level for the logger

See also

Logger::Verbosity

See also

Logger::set_verbosity

Returns:

The verbosity level of the logger

inline void set_log_level(espp::Logger::Verbosity level)

Set the log level for the logger

See also

Logger::Verbosity

See also

Logger::set_verbosity

Parameters:

level – The verbosity level to use for the logger

inline void set_log_verbosity(espp::Logger::Verbosity level)

Set the log verbosity for the logger

See also

set_log_level

See also

Logger::Verbosity

See also

Logger::set_verbosity

Note

This is a convenience method that calls set_log_level

Parameters:

level – The verbosity level to use for the logger

inline espp::Logger::Verbosity get_log_verbosity() const

Get the log verbosity for the logger

See also

get_log_level

See also

Logger::Verbosity

See also

Logger::get_verbosity

Note

This is a convenience method that calls get_log_level

Returns:

The verbosity level of the logger

inline void set_log_rate_limit(std::chrono::duration<float> rate_limit)

Set the rate limit for the logger

See also

Logger::set_rate_limit

Note

Only calls to the logger that have _rate_limit suffix will be rate limited

Parameters:

rate_limit – The rate limit to use for the logger

Public Static Functions

static inline MatouchRotaryDisplay &get()

Access the singleton instance of the MatouchRotaryDisplay class.

Returns:

Reference to the singleton instance of the MatouchRotaryDisplay class

static inline constexpr size_t lcd_width()

Get the width of the LCD in pixels

Returns:

The width of the LCD in pixels

static inline constexpr size_t lcd_height()

Get the height of the LCD in pixels

Returns:

The height of the LCD in pixels

static inline constexpr auto get_lcd_dc_gpio()

Get the GPIO pin for the LCD data/command signal

Returns:

The GPIO pin for the LCD data/command signal