So I want to control multiple (12) RGB LEDs using the raspberry pi. I have 6 connected to the GPIO ports on the pi itself and want 6 connected to 2 MCP23017. I cannot seem to get them both to show up when I run
i2cdetect -y 0.
Only the MCP23017 connected to the pi first, the lower one in the picture, shows up at address 0x20. Running 5v through it seemed to make that one show up but I think I may need a resistor of some kind to not fry the pi.
Can someone help me figure out either
A: Which resistor I need to safely run 5V to the pi.
B: How can I get both to show up using the 3.3V pin instead of the 5V.
This is the current wiring I have from the MCP23017s to the Pi.