Input Output Operations

Many times microprocessor has to  accept data  from input port and send data to  output  port to  interact with the  real world. Input  port is  tri state buffer  and output  port is  latch  tri state buffer  and latch  are already discussed in chapter. These input output ports  are identified by 8  bit address 8 bit port address of these input output ports may be any  of the 256 combinations of 8 bit  from 00H FFH. It means 8085  may communicate with  256 different  input  port and 256 different  output  ports. These input output ports are called  parallel port  i e 8 bit data is  transferred between  microprocessor and input output  port. Following s instruction  are used  to communicate  with input output.

Important: No  flags  are modified by input  output  operation.