Hi,  In your book LVGL version 1.1 page 143 code example has missing and reversed code.
void setup() {
String LVGL_Arduino = String(“LVGL Library Version: “) + lv_version_major()
+ “.” + lv_version_minor() + “.” + lv_version_patch();
Serial.begin(115200);
Serial.println(LVGL_Arduino);
pinMode(CYD_LED_RED, OUTPUT);
// configure LED PWM functionalities
ledcAttachChannel(CYD_LED_RED, freq, resolution, ledChannel)
ledcWrite(CYD_RED_LED, 255);
The last two lines are wrong.  Missing the; terminator and the ledcWrite should read (CYD_LED_RED).