I’m done here! The two files we worked on are finished.

Now we have the initializer and use of the MCP23017 (I’ll just write MCP from now on in this log). The addresses have been mapped and the registers too. You can see what happens along with the logic of keeping the line in the LOW state and the rest HIGH. In this part, it’s necessary to use masks and bitwise operations to see how it works. It stays in a loop analyzing what was pressed and, of course, if something strange happens outside the configuration, it throws an error saying UNKNOWN.