MAX14871 Motor Driver Arduino Class

max14871.hpp

#include <Arduino.h>

class Max14871 {
 public:
        Max14871(uint8_t pwm_pin, uint8_t dir_pin);
        void init(unsigned int pwm_freq);
        void set_duty_cycle(float duty);
        void set_speed(float speed);
        void enable(void);
        void disable(void);

 private:
        uint8_t _pwm_pin;
        uint8_t _dir_pin;
        unsigned int default_pwm_freq_hz = 20000u;
        unsigned int max_pwm_code = 0xFFFF;
        uint8_t pwm_res_bits = 16u;
        void config_pwm(unsigned int freq);
};

/**
 * constructor
 */
Max14871::Max14871(uint8_t pwm_pin, uint8_t dir_pin) {
    this->_pwm_pin = pwm_pin;
    this->_dir_pin = dir_pin;
}

/**
 * init pins and PWM timer
 * @param  {uint} unsigned int           pwm_freq pwm frequency in Hz
 * @return {none}          none
 */
void Max14871::init(unsigned int pwm_freq) {
    pinMode(this->_pwm_pin, OUTPUT);
    this->config_pwm(pwm_freq);
    this->enable();
}

/**
 * sets duty cycle on DIR pin
 * @param {float} float duty duty cycle from 0.0 - 1.0
 */
void Max14871::set_duty_cycle(float duty) {
    if (duty > 1.0f)
        duty = 1.0f;
    else if (duty < 0.0f)
        duty = 0.0f;
    unsigned int output = \
        (unsigned int)((float)duty*(float)this->max_pwm_code);
    analogWrite(this->_dir_pin, output);
}

/**
 * set speed from -1.0 to 1.0
 * @param {float} float speed normalized angular velocity of motor
 */
void Max14871::set_speed(float speed){
    if (speed < -1.0)
        speed = -1.0;
    if (speed > 1.0)
        speed = 1.0;
    float duty = (speed * 0.5) + 0.5;
    this->set_duty_cycle(duty);
}

/**
 * enable output, PWM pin on driver used as enable
 */
void Max14871::enable(void) {
    digitalWrite(this->_pwm_pin, 1);
}

/**
 * disable output, PWM pin on driver used as enable
 */
void Max14871::disable(void) {
    digitalWrite(this->_pwm_pin, 0);
}

/**
 * set pwm frequenct
 * @param  {uint} unsigned int           freq freq in Hz
 * @return {none}          none
 */
void Max14871::config_pwm(unsigned int freq) {
    if (freq < 0)
        freq = 1;
    else if (freq > 70000)
        freq = 70000;
    analogWriteResolution(this->pwm_res_bits);
    analogWriteFrequency(freq);
}