Basic functions

• DC_Motor (int pin1, int pin2)
  • This function will act to declare the pins being used to drive the DC motor
• start_motor ()
  • This function starts the motor in a specified direction. dir = 1 means CW and dir = -1 means CCW
  • Initialize PWM modules and drivers.
• forward()
  • This is done by writing PWM signals to across certain pins to the motor driver
• reverse()
  • This is done with the same PWM signals as above, but reversing the pin’s and the H-Bridge should handle the polarity reversal
• dc_break()
  • Instantly stops
    • Set duty Cycle to 0
• stop_motor()
  • Will slow to a stop
• set _speed(int speed)
  • This function will set the DC motor speed from 0-100%

PWM Testing:

Initial tests utilize halcogen’s NHET1 PWM signal generation code, which should generate a PWM signal with duty cycle of 75% and a period of 1000us.

Not sure why the signal is weird and not a square wave, but the duty cycle generated matches the expected generated PWM signal which is 750us of the wave being high and 250us of being low.

Test Cases for Motor

• [ ] varying PWM signals between large ranges in short periods of time
  • Essentially how fast can we switch between PWM signals and change the duty cycle to change the speed of the motor (response time for changing speed)
• [ ] variable speed test
• [ ] direction test

Some issues that I’m running into are actually changing the speed at run time, I expect that for future use, the duty cycle will be constantly be changing depending on the calculations from the algorithm.

There are also some setbacks on how to send a PWM signal only for a certain amount of time, currently that is a difficulty. I’ve tried using the <time.h> standard library with time_t struct to compare the initial start time and current runtime of the program to act as a timer, but to little success. I think a more elegant and suitable solution would be to utilize the RTI (Real time interrupt) module with events as a way to indicate how long we would like to send a PWM signal down to the NHET[0] pin for during runtime.