I2C Interfaced LCD

  1. Create I2C bus. Please refer to I2C API doc for more details.

    i2c_master_bus_handle_t i2c_bus = NULL;
i2c_master_bus_config_t bus_config = {
    .clk_source = I2C_CLK_SRC_DEFAULT,
    .glitch_ignore_cnt = 7,
    .i2c_port = I2C_BUS_PORT,
    .sda_io_num = EXAMPLE_PIN_NUM_SDA,
    .scl_io_num = EXAMPLE_PIN_NUM_SCL,
    .flags.enable_internal_pullup = true,
};
ESP_ERROR_CHECK(i2c_new_master_bus(&bus_config, &i2c_bus));

  2. Allocate an LCD IO device handle from the I2C bus. In this step, you need to provide the following information:

    esp_lcd_panel_io_handle_t io_handle = NULL;
esp_lcd_panel_io_i2c_config_t io_config = {
    .dev_addr = EXAMPLE_I2C_HW_ADDR,
    .scl_speed_hz = EXAMPLE_LCD_PIXEL_CLOCK_HZ,
    .control_phase_bytes = 1, // refer to LCD spec
    .dc_bit_offset = 6,       // refer to LCD spec
    .lcd_cmd_bits = EXAMPLE_LCD_CMD_BITS,
    .lcd_param_bits = EXAMPLE_LCD_CMD_BITS,
};
ESP_ERROR_CHECK(esp_lcd_new_panel_io_i2c(i2c_bus, &io_config, &io_handle));

  3. Install the LCD controller driver. The LCD controller driver is responsible for sending the commands and parameters to the LCD controller chip. In this step, you need to specify the I2C IO device handle that allocated in the last step, and some panel specific configurations:

    • esp_lcd_panel_dev_config_t::reset_gpio_num sets the LCD's hardware reset GPIO number. If the LCD does not have a hardware reset pin, set this to -1.

    • esp_lcd_panel_dev_config_t::bits_per_pixel sets the bit width of the pixel color data. The LCD driver uses this value to calculate the number of bytes to send to the LCD controller chip.

    esp_lcd_panel_handle_t panel_handle = NULL;
esp_lcd_panel_dev_config_t panel_config = {
    .bits_per_pixel = 1,
    .reset_gpio_num = EXAMPLE_PIN_NUM_RST,
};
ESP_ERROR_CHECK(esp_lcd_new_panel_ssd1306(io_handle, &panel_config, &panel_handle));

API Reference

Header File

  • components/esp_lcd/include/esp_lcd_io_i2c.h

  • This header file can be included with:

    #include "esp_lcd_io_i2c.h"

  • This header file is a part of the API provided by the esp_lcd component. To declare that your component depends on esp_lcd, add the following to your CMakeLists.txt:

    REQUIRES esp_lcd

    or

    PRIV_REQUIRES esp_lcd

Functions

esp_err_t esp_lcd_new_panel_io_i2c_v1(uint32_t bus, const esp_lcd_panel_io_i2c_config_t *io_config, esp_lcd_panel_io_handle_t *ret_io)

Create LCD panel IO handle, for I2C interface in legacy implementation.

Note

Please don't call this function in your project directly. Please call esp_lcd_new_panel_to_i2c instead.

Parameters

  • bus -- [in] I2C bus handle, (in uint32_t)

  • io_config -- [in] IO configuration, for I2C interface

  • ret_io -- [out] Returned IO handle

Returns

  • ESP_ERR_INVALID_ARG if parameter is invalid

  • ESP_ERR_NO_MEM if out of memory

  • ESP_OK on success

esp_err_t esp_lcd_new_panel_io_i2c_v2(i2c_master_bus_handle_t bus, const esp_lcd_panel_io_i2c_config_t *io_config, esp_lcd_panel_io_handle_t *ret_io)

Create LCD panel IO handle, for I2C interface in new implementation.

Note

Please don't call this function in your project directly. Please call esp_lcd_new_panel_to_i2c instead.

Parameters

  • bus -- [in] I2C bus handle, (in i2c_master_dev_handle_t)

  • io_config -- [in] IO configuration, for I2C interface

  • ret_io -- [out] Returned IO handle

Returns

  • ESP_ERR_INVALID_ARG if parameter is invalid

  • ESP_ERR_NO_MEM if out of memory

  • ESP_OK on success

Structures

struct esp_lcd_panel_io_i2c_config_t

Panel IO configuration structure, for I2C interface.

Public Members

uint32_t dev_addr

I2C device address

esp_lcd_panel_io_color_trans_done_cb_t on_color_trans_done

Callback invoked when color data transfer has finished

void *user_ctx

User private data, passed directly to on_color_trans_done's user_ctx

size_t control_phase_bytes

I2C LCD panel will encode control information (e.g. D/C selection) into control phase, in several bytes

unsigned int dc_bit_offset

Offset of the D/C selection bit in control phase

int lcd_cmd_bits

Bit-width of LCD command

int lcd_param_bits

Bit-width of LCD parameter

unsigned int dc_low_on_data

If this flag is enabled, DC line = 0 means transfer data, DC line = 1 means transfer command; vice versa

unsigned int disable_control_phase

If this flag is enabled, the control phase isn't used

struct esp_lcd_panel_io_i2c_config_t::[anonymous] flags

Extra flags to fine-tune the I2C device

uint32_t scl_speed_hz

I2C LCD SCL frequency (hz)

Macros

esp_lcd_new_panel_io_i2c(bus, io_config, ret_io)

Create LCD panel IO handle.

Parameters

  • bus -- [in] I2C bus handle

  • io_config -- [in] IO configuration, for I2C interface

  • ret_io -- [out] Returned IO handle

Returns

  • ESP_ERR_INVALID_ARG if parameter is invalid

  • ESP_ERR_NO_MEM if out of memory

  • ESP_OK on success

Type Definitions

typedef uint32_t esp_lcd_i2c_bus_handle_t

Type of LCD I2C bus handle

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