sleep mode for waveshare 4.3 inch ESP display

[mustafaakh10]

Hi,

I wanted to check if the library has a built-in feature for putting the display into sleep mode. I'm currently trying to achieve this by switching the backlight, but I'm starting to encounter I2C errors.

[Lzw655]

Hi @mustafaakh10,

Sorry, the feature to enter sleep mode is not provided yet. However, I will record it for subsequent updates.

Please describe the specific I2C errors and provide the corresponding log information.

[mustafaakh10]

Hi, thank you for your response.

What I'm specifically trying to achieve is the ability to turn off the screen after a period of inactivity, while keeping the ESP32 and all other functions—especially Wi-Fi—fully operational.

I previously attempted a similar implementation, but I started encountering I2C transaction errors, and afterward, I couldn't upload new sketches to the ESP32 without putting it into bootloader mode. The error logs included messages like:

E (...) lcd_panel.io.i2c: panel_io_i2c_tx_buffer(...): i2c transaction failed
E (...) GT911: esp_lcd_touch_gt911_read_data(...): I2C read error!

My goal is to implement a simple inactivity timer (e.g., 20 seconds), where the screen backlight turns off automatically if there's no user interaction, without triggering these I2C errors or interfering with normal operation.

Is there a reliable and clean way to achieve this?

Below are the functions i am using to for turning off and on the display

void turnOffScreen() {
if (screenOn) {
expander->digitalWrite(LCD_BL, LOW); // Turn off backlight
screenOn = false;
Serial.println("Screen turned OFF due to inactivity");
}
}

void turnOnScreen() {
if (!screenOn) {
expander->digitalWrite(LCD_BL, HIGH); // Turn on backlight
screenOn = true;
Serial.println("Screen turned ON due to user activity");
}
}

// Function to check touch input
bool checkUserActivity() {
lv_indev_t *indev = lv_indev_get_next(NULL);
while (indev) {
lv_indev_data_t data;
indev->driver->read_cb(indev->driver, &data);
if (data.state == LV_INDEV_STATE_PR) {
return true;
}
indev = lv_indev_get_next(indev);
}
return false;
}

[Lzw655]

This may be caused by Touch (GT911) and IO Expander sharing the same I2C bus. Please try to use lvgl_port_lock(-1) and lvgl_port_unlock() before and after operating them, as follows:

void turnOffScreen() {
if (screenOn) {
lvgl_port_lock(-1);
expander->digitalWrite(LCD_BL, LOW); // Turn off backlight
lvgl_port_unlock();
screenOn = false;
Serial.println("Screen turned OFF due to inactivity");
}
}

void turnOnScreen() {
if (!screenOn) {
lvgl_port_lock(-1);
expander->digitalWrite(LCD_BL, HIGH); // Turn on backlight
lvgl_port_unlock();
screenOn = true;
Serial.println("Screen turned ON due to user activity");
}
}

// Function to check touch input
bool checkUserActivity() {
lv_indev_t *indev = lv_indev_get_next(NULL);
lvgl_port_lock(-1);
while (indev) {
lv_indev_data_t data;
indev->driver->read_cb(indev->driver, &data);
if (data.state == LV_INDEV_STATE_PR) {
lvgl_port_unlock();
return true;
}
indev = lv_indev_get_next(indev);
}
lvgl_port_unlock();
return false;
}