Upload example code from https://osoyoo.com/2017/07/15/arduino-lesson-8x8-led-matrix/

snake.ino

@@ -0,0 +1,77 @@
+const int row[8] = {
+  2, 7, 19, 5, 13, 18, 12, 16
+};
+
+// 2-dimensional array of column pin numbers:
+const int col[8] = {
+  6, 11, 10, 3, 17, 4, 8, 9
+};
+
+// 2-dimensional array of pixels:
+int pixels[8][8];
+
+// cursor position:
+int x = 5;
+int y = 5;
+
+void setup() {
+  // initialize the I/O pins as outputs
+  // iterate over the pins:
+  for (int thisPin = 0; thisPin < 8; thisPin++) {
+    // initialize the output pins:
+    pinMode(col[thisPin], OUTPUT);
+    pinMode(row[thisPin], OUTPUT);
+    // take the col pins (i.e. the cathodes) high to ensure that
+    // the LEDS are off:
+    digitalWrite(col[thisPin], HIGH);
+  }
+
+  // initialize the pixel matrix:
+  for (int x = 0; x < 8; x++) {
+    for (int y = 0; y < 8; y++) {
+      pixels[x][y] = HIGH;
+    }
+  }
+}
+
+void loop() {
+  // read input:
+  readSensors();
+
+  // draw the screen:
+  refreshScreen();
+}
+
+void readSensors() {
+  // turn off the last position:
+  pixels[x][y] = HIGH;
+  // read the sensors for X and Y values:
+  x = 7 - map(analogRead(A0), 0, 1022, 0, 7);
+  y = map(analogRead(A1), 0, 1022, 0, 7);
+  // set the new pixel position low so that the LED will turn on
+  // in the next screen refresh:
+  pixels[x][y] = LOW;
+
+}
+
+void refreshScreen() {
+  // iterate over the rows (anodes):
+  for (int thisRow = 0; thisRow < 8; thisRow++) {
+    // take the row pin (anode) high:
+    digitalWrite(row[thisRow], HIGH);
+    // iterate over the cols (cathodes):
+    for (int thisCol = 0; thisCol < 8; thisCol++) {
+      // get the state of the current pixel;
+      int thisPixel = pixels[thisRow][thisCol];
+      // when the row is HIGH and the col is LOW,
+      // the LED where they meet turns on:
+      digitalWrite(col[thisCol], thisPixel);
+      // turn the pixel off:
+      if (thisPixel == LOW) {
+        digitalWrite(col[thisCol], HIGH);
+      }
+    }
+    // take the row pin low to turn off the whole row:
+    digitalWrite(row[thisRow], LOW);
+  }
+}