31 #define MD_DEFAULT_I2C_ADDR 0x0f 
   39         MD_REG_SET_SPEED           = 0x82,
 
   40         MD_REG_SET_PWM_FREQ        = 0x84,
 
   41         MD_REG_SET_DIRECTION       = 0xaa,
 
   42         MD_REG_SET_MOTOR_A         = 0xa1, 
 
   43         MD_REG_SET_MOTOR_B         = 0xa5, 
 
   44         MD_REG_STEPPER_ENABLE      = 0x1a,
 
   45         MD_REG_STEPPER_DISABLE     = 0x1b,
 
   46         MD_REG_STEPPER_NUM_STEPS   = 0x1c
 
   51         MD_STEP_DIR_CCW    = 0x01,
 
   53     } MD_STEP_DIRECTION_T;