espressif/esp_lcd_touch_cst816s

uploaded 3 months ago

# ESP LCD Touch CST816S Controller [](https://components.espressif.com/components/espressif/esp_lcd_touch_cst816s) Implementation of the CST816S touch controller with esp_lcd_touch component. | Touch controller | Communication interface | Component name | Link to datasheet | | :--------------: | :---------------------: | :-------------------: | :------------------------------------------------------------------------: | | CST816S | I2C | esp_lcd_touch_cst816s | [datasheet](https://www.buydisplay.com/download/ic/DS-CST816S_DS_V1.3.pdf) | **Note, there are two things about the driver are noteworthy (from [document](https://doc.riot-os.org/group__drivers__cst816s.html)):** * It only responds to I2C commands after an event, such as a touch detection. Do not expect it to respond on init. Instead after a touch event, it will assert the IRQ and respond to I2C reads for a short time. * While it should be able to detect multiple finger events, this version of the chip always returns only a single finger event and a gesture. Reading the display data multiple times during a single event will return the last sampled finger position. ## Add to project Packages from this repository are uploaded to [Espressif's component service](https://components.espressif.com/). You can add them to your project via `idf.py add-dependancy`, e.g. ``` idf.py add-dependency esp_lcd_touch_cst816s==1.0.0 ``` Alternatively, you can create `idf_component.yml`. More is in [Espressif's documentation](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/tools/idf-component-manager.html). ## Example use Define a mutex for the touch and create it before initialize the touch: ``` static SemaphoreHandle_t touch_mux; touch_mux = xSemaphoreCreateBinary(); ``` Define a callback function used by ISR: ``` static void touch_callback(esp_lcd_touch_handle_t tp) { BaseType_t xHigherPriorityTaskWoken = pdFALSE; xSemaphoreGiveFromISR(touch_mux, &xHigherPriorityTaskWoken); if (xHigherPriorityTaskWoken) { portYIELD_FROM_ISR(); } } ``` Initialization of the touch component. ``` esp_lcd_panel_io_i2c_config_t io_config = ESP_LCD_TOUCH_IO_I2C_CST816S_CONFIG(); esp_lcd_touch_config_t tp_cfg = { .x_max = CONFIG_LCD_HRES, .y_max = CONFIG_LCD_VRES, .rst_gpio_num = CONFIG_LCD_TOUCH_RST, .int_gpio_num = CONFIG_LCD_TOUCH_INT, .levels = { .reset = 0, .interrupt = 0, }, .flags = { .swap_xy = 0, .mirror_x = 0, .mirror_y = 0, }, .interrupt_callback = touch_callback, }; esp_lcd_touch_handle_t tp; esp_lcd_touch_new_i2c_cst816s(io_handle, &tp_cfg, &tp); ``` Read data from the touch controller and store it in RAM memory. It should be called regularly in poll. ``` if (xSemaphoreTake(touch_mux, 0) == pdTRUE) { esp_lcd_touch_read_data(tp); // read only when ISR was triggled } ``` Get one X and Y coordinates with strength of touch. ``` uint16_t touch_x[1]; uint16_t touch_y[1]; uint16_t touch_strength[1]; uint8_t touch_cnt = 0; bool touchpad_pressed = esp_lcd_touch_get_coordinates(tp, touch_x, touch_y, touch_strength, &touch_cnt, 1); ```