Partial display output: Only 7 out of 15 panels working on ESP32-S3 (3x5 matrix)

[Godwinner1213]

Hello,
I am working on a project using an ESP32-S3 N8R2 to drive a large LED matrix composed of 15 panels (32x32 pixels each) with a 1/4 scan rate. The panels are configured in a 3x5 matrix layout (Total resolution: 96x160 or 160x96 depending on orientation).
​The Setup:
​Hardware: ESP32-S3 N8R2 (2MB PSRAM).
​Library: ESP32-HUB75-MatrixPanel-I2S-DMA.
​Configuration: 15 panels, 1/4 Scan.
​The Problem:
The code compiles perfectly and the memory allocation (DMA/SRAM) completes successfully without any crashes or "Out of memory" errors during initialization. However, during execution, only the first 7 panels in the chain display the image correctly. The remaining 8 panels stay completely black.
​Observations:
​Allocation seems fine, but the data doesn't seem to reach the end of the chain.
​I have verified the power supply, and it is sufficient for the setup.
​I suspect it might be related to the maximum chain length supported by the DMA descriptors or a signal integrity issue over the long data lines.
​Could you please advise if there is a software limitation regarding the number of panels for 1/4 scan or if there are specific mxconfig tweaks required for long chains on the S3? I don't use Level Shifter(3.3V to 5V), could it be this?
​Best regards.

[board707]

Did tried to swap panels in chain?

[Godwinner1213]

Yes I did but no change and is similar with ESP32S

[Godwinner1213]

Hello @board707 I'm still waiting for a suggestion... Six months ago I had done a test, with the same configuration and the same code and the result was correct, but I think that since the last update of ESP-IDF some limitations have been inserted or something like that !? Your help is essential to me.

[mrcodetastic]

Can you try running any sketch without using the virtual matrix class? See if you get any output. Given these are 1/4 scan panels, that's actually a resolution (for this library) of 32x15x2 wide = 960 pixel, and a height of 16.

Also print any debug information here please, compile with the debug level set to verbose.

If you still don't get any output from that panel onwards, then the problem is most likely your electrical grounding. Have you checked the +5V and GND connection on panel 8? Given they're all connected in series, explains why everything after panel 8 is blank.

[board707]

I'm still waiting for a suggestion... I think that since the last update of ESP-IDF some limitations have been inserted or something like that !?

Hi
I can't comment on this because I'm not the author of the library's core code. My work only concerns the virtual matrix class for 4S panels.
I'm happy to help, but I don't know the internal details of ESP-IDF core.