I’m using an Arduino UNO which is currently connected to 2 I2C Qwiic mux breakout boards each with 8 ports (the plan is to expand up to 8 mux boards so we can have 512 I/O pins total). I have connected a Qwiic GPIO board to each port allowing me to expand up to 64 I/O pins per mux board. However, upon trying to read all the I/O pin statuses across both mux boards, the program I have suddenly fails and is “unable to detect the GPIO boards”. It’s especially weird because I can have 15 GPIO boards connected across two mux breakout boards but when I connect the 16th board, connection is suddenly lost. My suspicion is somehow the I2C bus is getting overloaded, but I’m not sure why or how. How can I resolve this issue?
You are likely maxing out the current/power that the qwiic lines can source, or creating a ton of pull-up resistance (maybe both…disable all but one set of i2c pull ups, you could disable the power LEDs on the GPIO boards as well to save on power https://learn.sparkfun.com/tutorials/sp … e-overview)
In my experiences it might help to split the project in half and have a 2nd MCU running 8 and the 1st one running a separate mux & 8…