Runtime Exception with ESP32

[ChaseParate]

• Arduino board: DOIT ESP32 DEVKIT V1

• Arduino IDE version (found in Arduino -> About Arduino menu): 1.8.19

• List the steps to reproduce the problem below (if possible attach a sketch or copy the sketch code in too):

  • I've wired up my ESP32 to my official Adafruit 32x16 LED matrix.

  • Using this simple sketch, I get an error in the Serial Monitor:

    #include <RGBmatrixPanel.h>
    
    #define A_PIN 23
    #define B_PIN 19
    #define C_PIN 5
    #define CLK_PIN 16
    #define LAT_PIN 4
    #define OE_PIN 15
    
    #define R1_PIN 25
    #define G1_PIN 26
    #define B1_PIN 27
    #define R2_PIN 14
    #define G2_PIN 12
    #define B2_PIN 13
    
    const unsigned int pinlist[] = {R1_PIN, G1_PIN, B1_PIN, R2_PIN, G2_PIN, B2_PIN};
    RGBmatrixPanel matrix(A_PIN, B_PIN, C_PIN, CLK_PIN, LAT_PIN, OE_PIN, false, pinlist);
    
    void setup() {
      Serial.begin(115200);
      matrix.begin();
    
      Serial.println("Is anyone there?");
    }
    
    void loop() {
    }

  • The aforementioned error is:

    Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled.
    Core 1 register dump:
    PC      : 0x40081969  PS      : 0x00060030  A0      : 0x800d101e  A1      : 0x3ffb1f10 
    A2      : 0x00000007  A3      : 0x00000002  A4      : 0x80086a78  A5      : 0x3ffba320 
    A6      : 0x00000001  A7      : 0x40084368  A8      : 0x3f40094c  A9      : 0xffffffff 
    A10     : 0xffffffff  A11     : 0x00000064  A12     : 0x08000000  A13     : 0x3ffbca00 
    A14     : 0xffffffff  A15     : 0x00000000  SAR     : 0x0000001a  EXCCAUSE: 0x0000001c 
    EXCVADDR: 0xffffffff  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000 
    
    ELF file SHA256: 0000000000000000
    
    Backtrace: 0x40081969:0x3ffb1f10 0x400d101b:0x3ffb1f30 0x400d0c54:0x3ffb1f90 0x400d204a:0x3ffb1fb0 0x40086a75:0x3ffb1fd0

  • Finally, I tried inspecting the backtrace, and got this as a result:

    Decoding stack results
    0x40081969: __pinMode at C:\Users\Chase\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.6\cores\esp32\esp32-hal-gpio.c line 106
    0x400d101b: RGBmatrixPanel::begin() at C:\Users\Chase\Documents\Arduino\libraries\RGB_matrix_Panel\RGBmatrixPanel.cpp line 314
    0x400d204a: String::changeBuffer(unsigned int) at C:\Users\Chase\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.6\cores\esp32\WString.cpp line 167
    0x40086a75: xQueueTakeMutexRecursive at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/queue.c line 651

Since this error seems to be happening in the RGBmatrixPanel::begin() function, I thought I'd post here for help. I've also created a post on the forums for this issue.

Thanks! Chase

[marcmerlin]

I'm not sure how stable or new the ESP32 code is, but may I recommend this library instead? https://github.com/pixelmatix/SmartMatrix If you want GFX support, you can add https://github.com/marcmerlin/SmartMatrix_GFX

This will also give you 24bppp support

[ChaseParate]

This seems to be some kind of null-pointer exception. The ptr variable in the updateDisplay function is a null-pointer that is trying to be dereferenced.

[ladyada]

https://github.com/adafruit/Adafruit_Protomatter supports ESP32 but not this library