Determine control words when the ports of Intel 8255 are defined as follows:

Port A as an input port. Mode of the Port A is Mode 0.
Port B as an input port. Mode of the Port B is Mode 0.
Port C upper and C lower are input ports.
b) Determine the control word for the following configuration of the ports of Intel 8255 for Mode 1 operation:
Port A is used as input and operation mode of Port A is Mode 1.
Port B can be used as output and operates in Mode 1.
PC6 and PC7 act as input.

c) Write down the port addresses of the three counters and the control word register. The Chip Select signal is derived on the basis of A7 – A4 =1111 and A3 – A2 = 00. Also, draw the interfacing diagram of Programmable Interval Timer 8254 with 8086. Assume suitable address mapping.