brief introduction: An I/O module is a subsystem in an integrated circuit that performs the functionality specific to interfacing a CPU to the rest of the system. It can also refer to configurable switches called I/O relay modules for switching the power to an external load. It can also refer to a programmable logic controller (PLC) that is used in industrial and manufacturing applications for performing functions like motor control. I/O modules within a microcontroller or microprocessor are usually memory mapped w