motor.cpp

00001 #include "mbed.h"
00002 #include "motor.h"
00003 
00004 
00005 Motor::Motor(MicroBit & bit)
00006     : _bit(bit),
00007       _speed(0),
00008       _targetSpeed(0)
00009 {
00010     // 50% duty cycle will make a nice step pulse
00011     SetPWMDutyCycle(900);
00012 }
00013 
00014 void Motor::SetSpeed(float targetSpeed)
00015 {
00016     _targetSpeed = targetSpeed;
00017 }
00018 
00019 float Motor::Speed()
00020 {
00021     return _speed;
00022 }
00023 
00024 void Motor::Step()
00025 {
00026     if ((_speed - _targetSpeed) > ACCELERATION)
00027         _speed -= ACCELERATION;
00028     else if ((_speed - _targetSpeed) < -ACCELERATION)
00029         _speed += ACCELERATION;
00030     else
00031         _speed = _targetSpeed;
00032  
00033     if ((_speed < 0.00005) && (_speed > -0.00005))
00034         _speed = 0.00005; // Prevent int overflow in SetPWMPeriod. 
00035         
00036     SetPWMPeriod(abs(100000/_speed));
00037 }
00038 
00039 void Motor::SetPWMDutyCycle(int value) const
00040 {
00041     _bit.io.P3.setAnalogValue(value);
00042     _bit.io.P4.setAnalogValue(value);
00043 }
00044  
00045 void Motor::SetPWMPeriod(int usValue) const
00046 {
00047     _bit.io.P3.setAnalogPeriodUs(usValue); 
00048     _bit.io.P4.setAnalogPeriodUs(usValue);
00049 }
00050 
00051 void Motor::SetDirection(STEP_DIRECTION direction) const
00052 {
00053     _bit.io.P8.setDigitalValue(direction);
00054     _bit.io.P16.setDigitalValue(direction);
00055 }
00056