- The port mode of the interface describes the direction of the data flow with respect to the component
- The five types of data flow are
- In - data flows in this port and can only be read
- Out - data flows out this port and can only be written to
- Buffer - data flow can be in either direction but only one source is allowed at any one time
- Inout - data flow can be in either direction with any number of sources allowed (implies a bus)
- Linkage - data flow direction is unknown
