PwmOut.cc

00001 #include <math.h> //For round
00002 #define NUMBER_PWM_STEPS 5000  //5000 steps between 0 and 1.
00003 namespace CPPToPigpio{
00004     PwmOut::PwmOut(PinName pin) : _pin(pin), _pwmValue(0.0f) 
00005     {
00006         CPPToPigpio::_handlePigpioInitialisationIfNeeded();
00007         //pigpio pwm is based on number of possible steps between fully off and on. Have to convert from %-time on to this step amount
00008         gpioSetPWMrange(static_cast<int>(pin), NUMBER_PWM_STEPS); 
00009         PwmOut::write(_pwmValue);
00010     }
00011 
00012     PwmOut::PwmOut(PinName pin, float val) : _pin(pin), _pwmValue(val) 
00013     {
00014         CPPToPigpio::_handlePigpioInitialisationIfNeeded();
00015         gpioSetPWMrange(static_cast<int>(pin), NUMBER_PWM_STEPS); 
00016         PwmOut::write(_pwmValue);
00017     }
00018 
00019     PwmOut::PwmOut(int pin) : _pin(static_cast<PinName>(pin)), _pwmValue(0.0f) 
00020     {
00021         //pigpio pwm is based on number of possible steps between fully off and on. Have to convert from %-time on to this step amount
00022         CPPToPigpio::_handlePigpioInitialisationIfNeeded();
00023         gpioSetPWMrange(pin, NUMBER_PWM_STEPS); 
00024         PwmOut::write(_pwmValue);
00025     }
00026 
00027     PwmOut::PwmOut(int pin, float val) : _pin(static_cast<PinName>(pin)), _pwmValue(val) 
00028     {
00029         CPPToPigpio::_handlePigpioInitialisationIfNeeded();
00030         gpioSetPWMrange(pin, NUMBER_PWM_STEPS); 
00031         PwmOut::write(_pwmValue);
00032     }
00033 
00034 
00035     void PwmOut::write(float val)
00036     {
00037         unsigned int dutyCycle = round(val*((float) NUMBER_PWM_STEPS));
00038         gpioPWM(static_cast<int>(_pin), dutyCycle); 
00039     }
00040 
00041     float PwmOut::read()
00042     {
00043         //Recalculate the pwm duty cycle, since it's possible to get a different result than what was set by the user (if the input period*NUMBER_PWM_STEPS is not an int)
00044         unsigned numSteps = gpioGetPWMdutycycle(static_cast<int>(_pin));
00045         return (static_cast<float>(numSteps)/static_cast<float>(NUMBER_PWM_STEPS));
00046     }
00047 
00048     float PwmOut::period(float seconds)
00049     {
00050         //Depends on Pi PWM sample rate, default is 5 and for now not changing from that
00051         unsigned int freq = static_cast<int>(1.0f/seconds);
00052         return 1.0f/(static_cast<float>(gpioSetPWMfrequency(_pin, freq))); //Likely WILL NOT match input
00053     }
00054 
00055     float PwmOut::period_ms(int ms)
00056     {
00057         float seconds = static_cast<float>(ms)/1000.0f;
00058         unsigned int freq = static_cast<int>(1.0f/seconds);
00059         return 1.0f/(static_cast<float>(gpioSetPWMfrequency(_pin, freq)));
00060     }
00061 
00062     float PwmOut::period_us(int us)
00063     {
00064         float seconds = static_cast<float>(us)/1000000.0f;
00065         unsigned int freq = static_cast<int>(1.0f/seconds);
00066         return 1.0f/(static_cast<float>(gpioSetPWMfrequency(_pin, freq)));
00067     }
00068 
00069     PwmOut & PwmOut::operator=(float val)
00070     {
00071         PwmOut::write(val);
00072         return *this;
00073     }
00074 
00075     PwmOut & PwmOut::operator=(PwmOut & rhs)
00076     {
00077         PwmOut::write(rhs.read());
00078         return *this;
00079     }
00080 
00081     PwmOut::operator float()
00082     {
00083         return PwmOut::read();
00084     }
00085 
00086     PwmOut::~PwmOut()
00087     {
00088         CPPToPigpio::_handlePigpioTermination(); 
00089     }
00090 }
00091