8x8 LED matrix not working with LCD1602

I’m trying to hook up an 8x8 led matrix and an LCD display to my Arduino. The LCD display is working along with a joystick I’ve also added, but the 8x8 LED isn’t. Here’s
a diagram of the circuit.

Two problems.

  • No code.
  • Sharing your pins to the MAX7219 with your dispaly is almost certainly a bad idea onless you are very careful with your coding! :astonished:

Sharing the pins are not simple. To make the sharing work you have to make sure that:

1: That the LCD library does not "step" on the pins while you are not sending data to the display.
2: Make sure that the CS (Chip Select) pin is separate for what ever devices that are sharing their data pins. Sharing the CS-pin will only lead to problems.

Obeying these rules should make it possible to share some of the pins at least.

// Per.