programmable and nonprogrammable i/o ports

Non-programmable I/O Port: It behaves as an input port if it has been designed and connected in input mode. Similarly a port connected in output mode acts as an output port. Example: INTEL 8212 Programmable I/O Port: It can be programmed to act either as an input

port or output port. In both the cases the electrical connections remain same.
 

Example: INTEL 8212
 

Programmable I/O Port: It can be programmed to act either as an input port or output port. In both the cases the electrical connections remain same.
 

Example: INTEL 8255