This project is based on Motorola HC11 controller. This circuit is built to drive a stepper motor. A high or a low signal is given as input to rotate the stepper motor clockwise or anticlockwise respectively. To simulate this circuit, initially activate Mixed Mode simulator from the Schematic Editor window. Simulation can be performed by selecting Transient analysis from Simulation menu.
This project includes microcontroller M68HC11A8, stepper motor unit (interface and motor).
A high or a low signal is given as input to the 0th pin of PORT A of the microcontroller to rotate the stepper motor clockwise or anticlockwise. A high signal at the Port A drives the stepper motor clockwise and a low signal drives the stepper motor anticlockwise. The signal is given before invoking the simulation.
As the microcontroller cannot drive stepper motor directly, a motor driver IC (ULN 2003) is used. This is a Darlington octal buffer IC.
The source code written either in C or Assembly language can be viewed from the
code editor window.
The program is as shown:
BRCLR 0,X 0x01 ANTI ; Branch if the bit is clear
LDAA #0x01 ; Output the sequence to rotate clockwise to Port B