The command interface receives the command data message and has the goal to drive the RIP mechanical system using the amplifier circuit and the dc motor. To get these requirements we have implemented an application that performs: initialization of the I2C module, output ports and timer for the PWM signal, reading data from the I2C bus if are available, decoding data message received from the control interface in order to obtain the direction and the duty cycle of the PWM signal, formation of the output signals for direction and PWM command sent to the amplifier circuit.
Amplifier circuit is composed of the H-bridge driver which allows changing the direction of rotation and the speed of the dc motor by giving a voltage of appropriate magnitude. The power supply of the motor and its speed depends on the duty cycle of the PWM signal. The PWM signal has a 30kHzfrequency generated by the microcontroller timer. Also, some high speed optocouple were integrated before H-bridge driver to protect the microcontroller.