I am using MCP23017 as a GPIO expander with Arduino in my project. I have too many serial devices and no pins left on Arduino for UART communication.
I am wondering if I can use this MCP23017 GPIO expander pins for UART communication or not?
I can think of one way.
In theory you could use the GPIO pins of the mcp23017 to control a couple of 2-way multiplexers. With these multiplexers you could split your Rx/Tx pins to more than one serial bus.
May it be obvious that you cannot used the split busses at the same time. So depending on your specific use-case this may or may not be a solution.