ESP32-WROVER-KIT

Wrover-Kit

The ESP32-WROVER-KIT is a development board for the ESP32-WROVER module. It features a nice display and a lot of expansion headers.

The espp::WroverKit component provides a singleton hardware abstraction for initializing the display subsystems.

Wrover-Kit Example
- How to use example
  - Hardware Required
  - Build and Flash
- Example Output

API Reference

Header File

components/wrover-kit/include/wrover-kit.hpp

Classes

class WroverKit : public espp::BaseComponent 

The WroverKit class provides an interface to the ESP32-WROVER-KIT ESP32 development board.

The class provides access to the following features:

Display

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

Example

  espp::WroverKit &wrover = espp::WroverKit::get();
  wrover.set_log_level(espp::Logger::Verbosity::INFO);

  // initialize the LCD
  if (!wrover.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 = wrover.lcd_width() * 50;
  // initialize the LVGL display for the wrover-kit
  if (!wrover.initialize_display(pixel_buffer_size)) {
    logger.error("Failed to initialize display!");
    return;
  }

  logger.info("Adding LVGL objects to the screen.");

  // initialize the button, which we'll use to cycle the rotation of the display
  espp::Button button(espp::Button::Config{
      .name = "Boot Button",
      .interrupt_config =
          espp::Interrupt::PinConfig{.gpio_num = GPIO_NUM_0,
                                     .callback =
                                         [](const auto &event) {
                                           if (event.active) {
                                             // lock the display mutex
                                             std::lock_guard<std::mutex> lock(lvgl_mutex);
                                             static auto rotation = LV_DISPLAY_ROTATION_0;
                                             rotation = static_cast<lv_display_rotation_t>(
                                                 (static_cast<int>(rotation) + 1) % 4);
                                             fmt::print("Setting rotation to {}\n", (int)rotation);
                                             lv_display_t *disp = _lv_refr_get_disp_refreshing();
                                             lv_disp_set_rotation(disp, rotation);
                                           }
                                         },
                                     .active_level = espp::Interrupt::ActiveLevel::LOW,
                                     .interrupt_type = espp::Interrupt::Type::ANY_EDGE,
                                     .pullup_enabled = false,
                                     .pulldown_enabled = false},
  });

  // set the background color to black
  lv_obj_t *bg = lv_obj_create(lv_screen_active());
  lv_obj_set_size(bg, wrover.lcd_width(), wrover.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, "Drawing circles to the screen.");
  lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);
  lv_obj_set_style_text_align(label, LV_TEXT_ALIGN_CENTER, 0);

  // 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::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%
  wrover.brightness(75.0f);

  while (true) {
    auto start = esp_timer_get_time();
    // if there are 10 circles on the screen, clear them
    static constexpr int max_circles = 10;
    if (circles.size() >= max_circles) {
      std::lock_guard<std::mutex> lock(lvgl_mutex);
      clear_circles();
    } else {
      // draw a circle of circles on the screen (just draw the next circle)
      static constexpr int middle_x = wrover.lcd_width() / 2;
      static constexpr int middle_y = wrover.lcd_height() / 2;
      static constexpr int radius = 50;
      float angle = circles.size() * 2.0f * M_PI / max_circles;
      int x = middle_x + radius * cos(angle);
      int y = middle_y + radius * sin(angle);
      std::lock_guard<std::mutex> lock(lvgl_mutex);
      draw_circle(x, y, 10);
    }
    auto end = esp_timer_get_time();
    auto elapsed = end - start;
    std::this_thread::sleep_for(100ms - std::chrono::microseconds(elapsed));
  }

Public Types

using Pixel = lv_color16_t: Alias for the pixel type used by the wrover-kit display.

Public Functions

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, const espp::Task::BaseConfig &task_config={.name="Display",.stack_size_bytes=4096,.priority=10,.core_id=0}, int update_period_ms=16)

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
task_config – The task configuration for the display task
update_period_ms – The update period of the display task

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

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

float brightness() const

Get the brightness of the backlight

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_lcd(const uint8_t *data, size_t length, uint32_t user_data)

Write data 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

data – The data to write
length – The length of the data
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 WroverKit &get()

Access the singleton instance of the WroverKit class.

Returns: Reference to the singleton instance of the WroverKit 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

struct TouchpadData

The data structure for the touchpad.

Public Functions

bool operator==(const TouchpadData &rhs) const = default

Compare two TouchpadData objects for equality.

Parameters: rhs – The right hand side of the comparison
Returns: true if the two TouchpadData objects are equal, false otherwise

Public Members

uint8_t num_touch_points = 0: The number of touch points.

uint16_t x = 0: The x coordinate.

uint16_t y = 0: The y coordinate.

uint8_t btn_state = 0: The button state (0 = button released, 1 = button pressed)