Descibe 8086 interfacing of stepper motor to rotate it through 90 degree using 8255?

To interface a stepper motor with the 8086 microprocessor using the 8255 Programmable Peripheral Interface (PPI), you first configure the 8255 in mode 0 for simple I/O operations. The control lines of the stepper motor are connected to the output ports of the 8255. The microprocessor sends a sequence of pulses to these ports to energize the motor coils in the correct order, effectively rotating the motor in steps. To achieve a 90-degree rotation, the number of pulses sent corresponds to the required steps based on the step angle of the motor (e.g., for a 1.8-degree stepper, you would send 50 pulses).