Implementation of the XPT2046 Touch controller with esp_lcd_touch component.
| Touch controller | Communication interface | Component name | Link to datasheet |
|---|---|---|---|
| XPT2046 | SPI | esp_lcd_touch_xpt2046 | Specification |
This package can be added to your project in two ways:
- Using Espressif's component service as:
dependencies:
atanisoft/esp_lcd_touch_xpt2046: "~1.0.0"
- Using the git repository directly:
dependencies:
esp_lcd_touch_xpt2046:
git: https://github.com/atanisoft/esp_lcd_touch_xpt2046.git
For more information on the usage of the idf_component.yml file please refer to Espressif's documentation.
At this time testing is limited to ESP32 and ESP32-S3, other ESP32 variants should work but are not tested.
Kconfig.projbuild contains a handful of options to allow customization of the XPT2046 interface:
- XPT2046_Z_THRESHOLD - This is the minimum ADC threshold to use for detecting touch points.
- XPT2046_INTERRUPT_MODE - This option enables / disables the PENIRQ output from the chip. If enabled (and the
int_gpio_numis set) the driver can check for touch more efficiently by reading the input. - XPT2046_VREF_ON_MODE - This option enables / disables keeping the internal Vref permanently enabled. This uses more power, but requires fewer SPI transactions when reading the battery voltage, aux voltage and temperature.
- XPT2046_CONVERT_ADC_TO_COORDS - This option enables / disables the conversion of raw ADC values into screen coordinates. When disabled it will be necessary to define the
process_coordinatesmethod inesp_lcd_touch_config_t. This can be useful for applying calibration or other offsets to adjust the screen coordinates. - XPT2046_ENABLE_LOCKING - This option enables / disables the usage of critical sections to protect internal data structures. This has been seen to cause conflicts with other components at times.
esp_lcd_touch_handle_t tp = NULL;
esp_lcd_panel_io_handle_t tp_io_handle = NULL;
esp_lcd_panel_io_spi_config_t tp_io_config = ESP_LCD_TOUCH_IO_SPI_XPT2046_CONFIG(TOUCH_CS_PIN);
ESP_ERROR_CHECK(esp_lcd_new_panel_io_spi((esp_lcd_spi_bus_handle_t)SPI2_HOST, &tp_io_config, &tp_io_handle));
esp_lcd_touch_config_t tp_cfg = {
.x_max = CONFIG_LCD_HRES,
.y_max = CONFIG_LCD_VRES,
.rst_gpio_num = -1,
.int_gpio_num = -1,
.flags = {
.swap_xy = 0,
.mirror_x = 0,
.mirror_y = 0,
},
};
ESP_LOGI(TAG, "Initialize touch controller XPT2046");
ESP_ERROR_CHECK(esp_lcd_touch_new_spi_xpt2046(tp_io_handle, &tp_cfg, &tp));
This will read new data from the touch controller and store it in SRAM. This method should be called on a regular basis.
ESP_ERROR_CHECK(esp_lcd_touch_read_data(tp));
This will retrieve the latest averaged touch point data from SRAM.
uint16_t x[1];
uint16_t y[1];
uint16_t strength[1];
uint8_t count = 0;
bool touchpad_pressed = esp_lcd_touch_get_coordinates(tp, x, y, strength, &count, 1);
This driver can be integrated with LVGL using code similar to below:
void touch_driver_read(lv_indev_drv_t *drv, lv_indev_data_t *data)
{
uint16_t x[1];
uint16_t y[1];
uint16_t strength[1];
uint8_t count = 0;
// Update touch point data.
ESP_ERROR_CHECK(esp_lcd_touch_read_data(tp));
data->state = LV_INDEV_STATE_REL;
if (esp_lcd_touch_get_coordinates(tp, x, y, strength, &count, 1))
{
data->point.x = x[0];
data->point.y = y[0];
data->state = LV_INDEV_STATE_PR;
}
data->continue_reading = false;
}
void initialize_input()
{
lv_indev_drv_t indev_drv;
lv_indev_drv_init( &indev_drv );
indev_drv.type = LV_INDEV_TYPE_POINTER;
indev_drv.read_cb = touch_driver_read;
lv_indev_drv_register( &indev_drv );
}
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