Hi
Does LVGL include a multitasking function? Do all other functions that use LVGL need to use the built-in function to handle multitasking, such as display and touch panel?
If I need to use an RTOS, like FreeRTOS, how do I do that? Are there any tutorial resources you can recommend?
For a simple application, could we use a simple timer interrupt (e.g. ring wheel)?
My goal is to create a program using LVGL (Squareline Studio) to control several PWM outputs, LEDs, and communicate with sensors. While I can code for each of these functions individually, I’m not sure how to integrate them together. If I simply merge them, the performance may be blocked by one another. For example, the PWM signal may be affected or blocked by GUI updates or input.
MCU/Processor/Board = ESP32
compiler = PlatformIO with Arduino framework
LVGL version = v8.3
I’m not asking for a complete code, but I would appreciate if you could provide an example or tutorial for me to study and try out myself.
#include <Arduino.h>
#include <TAMC_GT911.h>
#include <lvgl.h>
#include <TFT_eSPI.h>
#include <ui.h>
hw_timer_t * timer = NULL; // create a timer object
void IRAM_ATTR onTimer()
{ // timer interrupt handler function
// do something on timer interrupt
lv_timer_handler(); /* let the GUI do its work */
}
/*Don't forget to set Sketchbook location in File/Preferencesto the path of your UI project (the parent foder of this INO file)*/
/*Change to your screen resolution*/
static const uint16_t screenWidth = 480;
static const uint16_t screenHeight = 320;
static lv_disp_draw_buf_t draw_buf;
static lv_color_t buf[ screenWidth * screenHeight / 10 ];
TFT_eSPI tft = TFT_eSPI(screenWidth, screenHeight); /* TFT instance */
//myTest
#define TOUCH_SDA 21
#define TOUCH_SCL 22
#define TOUCH_INT 25
#define TOUCH_RST 26
#define TOUCH_WIDTH screenWidth
#define TOUCH_HEIGHT screenHeight
TAMC_GT911 tp = TAMC_GT911(TOUCH_SDA, TOUCH_SCL, TOUCH_INT, TOUCH_RST, TOUCH_WIDTH, TOUCH_HEIGHT);
#define LED_GPIO 14
#if LV_USE_LOG != 0
/* Serial debugging */
void my_print(const char * buf)
{
Serial.printf(buf);
Serial.flush();
}
#endif
/* Display flushing */
void my_disp_flush( lv_disp_drv_t *disp, const lv_area_t *area, lv_color_t *color_p )
{
uint32_t w = ( area->x2 - area->x1 + 1 );
uint32_t h = ( area->y2 - area->y1 + 1 );
tft.startWrite();
tft.setAddrWindow( area->x1, area->y1, w, h );
tft.pushColors( ( uint16_t * )&color_p->full, w * h, true );
tft.endWrite();
lv_disp_flush_ready( disp );
}
/*Read the touchpad*/
void my_touchpad_read( lv_indev_drv_t * indev_driver, lv_indev_data_t * data )
{
//myTest
tp.read();
if(tp.isTouched)
{
data->state = LV_INDEV_STATE_PR;
data->point.x = tp.points[0].x;
data->point.y = tp.points[0].y;
}
else
{
data->state = LV_INDEV_STATE_REL;
}
}
void setup()
{
Serial.begin( 115200 ); /* prepare for possible serial debug */
String LVGL_Arduino = "Hello Arduino! ";
LVGL_Arduino += String('V') + lv_version_major() + "." + lv_version_minor() + "." + lv_version_patch();
Serial.println( LVGL_Arduino );
Serial.println( "I am LVGL_Arduino" );
//myTest
tp.begin();
tp.setRotation(ROTATION_LEFT);
lv_init();
#if LV_USE_LOG != 0
lv_log_register_print_cb( my_print ); /* register print function for debugging */
#endif
tft.begin(); /* TFT init */
tft.setRotation( 3 ); /* Landscape orientation, flipped */
lv_disp_draw_buf_init( &draw_buf, buf, NULL, screenWidth * screenHeight / 10 );
/*Initialize the display*/
static lv_disp_drv_t disp_drv;
lv_disp_drv_init( &disp_drv );
/*Change the following line to your display resolution*/
disp_drv.hor_res = screenWidth;
disp_drv.ver_res = screenHeight;
disp_drv.flush_cb = my_disp_flush;
disp_drv.draw_buf = &draw_buf;
lv_disp_drv_register( &disp_drv );
/*Initialize the (dummy) input device driver*/
static lv_indev_drv_t indev_drv;
lv_indev_drv_init( &indev_drv );
indev_drv.type = LV_INDEV_TYPE_POINTER;
indev_drv.read_cb = my_touchpad_read;
lv_indev_drv_register( &indev_drv );
ui_init();
Serial.println( "Setup done" );
//myTest
pinMode(TFT_BL, OUTPUT);
digitalWrite(TFT_BL,HIGH);
pinMode(LED_GPIO, OUTPUT);
digitalWrite(LED_GPIO,LOW);
timer = timerBegin(0, 80, true); // use timer 0, prescaler 80, count up
timerAttachInterrupt(timer, &onTimer, true); // attach the interrupt handler function to the timer
timerAlarmWrite(timer, 1000000, true); // set the timer alarm to 1 second, repeat timer
timerAlarmEnable(timer); // enable the timer alarm
//lv_label_set_text(ui_Label1, "------");
}
void loop()
{
//lv_timer_handler(); /* let the GUI do its work */
delay(5);
//delay(2000);
//lv_label_set_text(ui_Label1, "------");
}
