Display flicker with

[CambridgeStateMachines]

Hi, I would like to program my Tab5 in C using Arduino IDE and LVGL v9.4 and I used your demo for guidance. The code compiles, transfers and runs, but I have uncontrollable screen flicker.

My Tab5 dates from after 14 October 2025 when M5Stack changed the display / touch drivers from ILI9881C / GT911 respectively to an integrated display‑touch driver: ST7123. I have confirmed that the display is not faulty by uploading and running non-LVGL programs.

See link below with details of the driver change:

https://docs.m5stack.com/en/core/Tab5?id=Version%20Change

Does your Tab5 pre-dates 14 October 2025?

Cheers, CSM

[nikthefix]

@CambridgeStateMachines
Yes I got one of the very first Tab5 units - ordered on the first day they appeared on the M5stack website.
I'll take a look at the version change and see if there's a quick fix.

Edit: Since my original demo code used the M5GFX library which was the latest at the time I would expect the current latest version of the library to have implemented changes to accommodate the new hardware.

I can confirm that my older Tab5 runs the latest M5stack M5GFX demos fine.
If you're using LVGL 9.x then my demo will fail as 9.x does not support the display software rotate function:

disp_drv.sw_rotate = 1;
disp_drv.rotated = LV_DISP_ROT_90;

Soft rotation must be implemented by the coder in the 'display flush' callback function.
Also, for partial update, the 'rounder' callback function may need to be modified as the new display hardware may have different rules.

It also looks like the new display uses an increased DPI clock (from 60 to 70MHz) and uses double frame buffering by default in M5GFX.

Unfortunately I don't have a recent Tab5 for testing.

[CambridgeStateMachines]

Hi, thanks for your reply. Your demo works fine on my Tab5. I can see and interact with the widgets, I just have an uncontrollable screen flicker. I added Serial functions and can see that everything is working fine, apart from screen stability.

I had a look at the source code of the official Tab5 demo which works on my Tab5 with no flicker. Unfortunately, it was written for ESP-IDF and is therefore not immediately portable to Arduino.

However, the demo's components folder includes a ST7123 driver and there is a corresponding header in the priv_include folder.

There are no obvious clues in the demo's lv_conf.h file other than confirmation that the demo was created with LVGL v9.2.0.

I'm going to see if I can work through the official demo and extract the minimum code required to get a simple flicker-free app going in Arduino with LVGL v9.2.0.

Thanks again for your time!

Edit: I'm beginning to think that this is a HW issue with my Tab5. Even the simplest Arduino sketches (including Arduino's official examples) have the screen flicker issue. I've ordered a new Tab5 to confirm whether or not my original unit is faulty.