INTERFACING TO A MICROPROCESSOR CONTROLLER – The Parallel Interface
The parallel interface transfers data 8 bits (or more) at the same time, using eight separate wires. It is essentially an extension of the data bus into the outside world. The parallel interface is ideal for inputting or outputting data from devices that are either on or off. For example, a single limit switch uses only one input bit, and an on-off signal to a motor requires only one output bit. These 1-bit signals are called logic variables, and eight such signals can be provided from a single (8-bit) port. This concept
will be expanded on later in this section.