A question about LVGL

General discussion
1

I have a question about the lvgl version 8.3.11(arduino IDE),so i have an esp32 knob that uses lvgl library.

For context i have an esp32 miucro-controller that communicates with an exp32 knob that uses lvgl library(uart communication), then the knob will receives the command and use “lv_textarea_set_text” for example to change a text zone(firmware example im using:UEDX24240013-MD50ESP32_1.3inch-Knob/examples/Arduino/SquareLinePorting at main · VIEWESMART/UEDX24240013-MD50ESP32_1.3inch-Knob · GitHub).

now my question is does the knob parse data when i call “lv_textarea_set_text” or its just a string processing act? and if the knob parses data,is it a simple parse or multiple parses?

2

Hi @Mounirba98, if I understood you correctly, you have two ESP32s in this architecture:

ESP32 ----UART----> ESP32 Knob with LVGL

Which one are you trying to program?

In the link you gave, I didn’t see any example of UART communication.

3

i can’t share the full code,even the link i shared is the project example that i used as a start point,the main board’s esp32 sends command to esp32 knob, and an if statement will make sure that its the right command and execute it,for example the esp32 in the main board sends “next screen” and the esp32 knob will receive the command,and an the if statement works like this
//**************
if (received_msg == “next screen”) _ui_screen_change(&ui_scr1, LV_SCR_LOAD_ANIM_NONE, 5, 0, &ui_scr1_init);
//****************
I can’t share any part of the real code because its confidential.

4

No problem, I’ve worked with similar projects and the way they worked was in a master/slave communication, where the display/IHM, the knob in your case, was just receiveing commands. I think thats your case.

These products used a serial communication protocol to be able to communicate, but in the majority of cases this protocol are proprietary, but most of them are a copy of each other hahaha. You can use these protocols as a base to build your own, not so hard to find the specifications.

I think you are in right track, just don’t use plain strings.