That’s what I thought about doing (using an oscilloscope) but I don’t have one at home, I could use the ones in school but due to corona, there are some strict rules. The first LED on the second matrix doesn’t light up, maybe that one is fried and broke the data line. I will check it out more thoroughly later. The code is from a simple example from neomatrix library.

```
// Adafruit_NeoMatrix example for tiled NeoPixel matrices. Scrolls
// 'Howdy' across three 10x8 NeoPixel grids that were created using
// NeoPixel 60 LEDs per meter flex strip.
#include <Adafruit_GFX.h>
#include <Adafruit_NeoMatrix.h>
#include <Adafruit_NeoPixel.h>
#ifndef PSTR
#define PSTR // Make Arduino Due happy
#endif
#define PIN 6
// MATRIX DECLARATION:
// Parameter 1 = width of EACH NEOPIXEL MATRIX (not total display)
// Parameter 2 = height of each matrix
// Parameter 3 = number of matrices arranged horizontally
// Parameter 4 = number of matrices arranged vertically
// Parameter 5 = pin number (most are valid)
// Parameter 6 = matrix layout flags, add together as needed:
// NEO_MATRIX_TOP, NEO_MATRIX_BOTTOM, NEO_MATRIX_LEFT, NEO_MATRIX_RIGHT:
// Position of the FIRST LED in the FIRST MATRIX; pick two, e.g.
// NEO_MATRIX_TOP + NEO_MATRIX_LEFT for the top-left corner.
// NEO_MATRIX_ROWS, NEO_MATRIX_COLUMNS: LEDs WITHIN EACH MATRIX are
// arranged in horizontal rows or in vertical columns, respectively;
// pick one or the other.
// NEO_MATRIX_PROGRESSIVE, NEO_MATRIX_ZIGZAG: all rows/columns WITHIN
// EACH MATRIX proceed in the same order, or alternate lines reverse
// direction; pick one.
// NEO_TILE_TOP, NEO_TILE_BOTTOM, NEO_TILE_LEFT, NEO_TILE_RIGHT:
// Position of the FIRST MATRIX (tile) in the OVERALL DISPLAY; pick
// two, e.g. NEO_TILE_TOP + NEO_TILE_LEFT for the top-left corner.
// NEO_TILE_ROWS, NEO_TILE_COLUMNS: the matrices in the OVERALL DISPLAY
// are arranged in horizontal rows or in vertical columns, respectively;
// pick one or the other.
// NEO_TILE_PROGRESSIVE, NEO_TILE_ZIGZAG: the ROWS/COLUMS OF MATRICES
// (tiles) in the OVERALL DISPLAY proceed in the same order for every
// line, or alternate lines reverse direction; pick one. When using
// zig-zag order, the orientation of the matrices in alternate rows
// will be rotated 180 degrees (this is normal -- simplifies wiring).
// See example below for these values in action.
// Parameter 7 = pixel type flags, add together as needed:
// NEO_RGB Pixels are wired for RGB bitstream (v1 pixels)
// NEO_GRB Pixels are wired for GRB bitstream (v2 pixels)
// NEO_KHZ400 400 KHz bitstream (e.g. FLORA v1 pixels)
// NEO_KHZ800 800 KHz bitstream (e.g. High Density LED strip)
// Example with three 10x8 matrices (created using NeoPixel flex strip --
// these grids are not a ready-made product). In this application we'd
// like to arrange the three matrices side-by-side in a wide display.
// The first matrix (tile) will be at the left, and the first pixel within
// that matrix is at the top left. The matrices use zig-zag line ordering.
// There's only one row here, so it doesn't matter if we declare it in row
// or column order. The matrices use 800 KHz (v2) pixels that expect GRB
// color data.
Adafruit_NeoMatrix matrix = Adafruit_NeoMatrix(10, 8, 3, 1, PIN,
NEO_TILE_TOP + NEO_TILE_LEFT + NEO_TILE_ROWS + NEO_TILE_PROGRESSIVE +
NEO_MATRIX_TOP + NEO_MATRIX_LEFT + NEO_MATRIX_COLUMNS + NEO_MATRIX_ZIGZAG,
NEO_GRB + NEO_KHZ800);
const uint16_t colors[] = {
matrix.Color(255, 0, 0), matrix.Color(0, 255, 0), matrix.Color(0, 0, 255) };
void setup() {
matrix.begin();
matrix.setTextWrap(false);
matrix.setBrightness(40);
matrix.setTextColor(colors[0]);
}
int x = matrix.width();
int pass = 0;
void loop() {
matrix.fillScreen(0);
matrix.setCursor(x, 0);
matrix.print(F("Howdy"));
if(--x < -36) {
x = matrix.width();
if(++pass >= 3) pass = 0;
matrix.setTextColor(colors[pass]);
}
matrix.show();
delay(100);
}
```