TCA9546a and mcp23017

[Anno]

I have made a esp8266 with a TCA9546a and a mcp23017 on the same bus with 2 different addresses.

I use the firmware 23-03.

The problem is when I activate the multiplexer. The mcp is gone and won't work anymore. I think this is a software problem. Both do work but not together.

[Ath]

Is it recognized by the I2C scanner once the multiplexer is enabled? (It may display only the I2C address (hexadecimal) depending on the type of .bin you have installed)

Can you connect it to 1 of the output channels of the I2C multiplexer? That should work as intended. Be aware that the multiplexer doesn't come with pull-up resistors, but requires them on the I2C bus, both on the input channel and output channels (those that are in use). 10k each between SDA and SCL and 3.3V is fine for short wiring (less than 1 meter).