Write 8086 initialisation routine required to program 8255 for mode 1 with Port A and Port B as output Ports and Port C as an input port. Indicate all the relevant signals.

• A, B can only change 1 byte at a time
• C has individual bit set/reset capability
• The Advantage is that non-dedicated circuit can change port configuration with software and no 'glue logic'.
• Ports A, B, and C are used for I/O data.
• Control register is programmed to select the operation mode of the three ports A, B, and C.
• Mode0: simple I/O mode
• Any of the ports A, B, CL and CU can be programmed as input or output.
• No control of individual bits (all bits are out or all bits are in)