dualpwm.h

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#pragma once
 
#include <PropWare/concurrent/runnable.h>
#include <PropWare/gpio/pin.h>
 
namespace PropWare {
 
class DualPWM: public Runnable {
    public:
        static const unsigned int MAX_DUTY = 4096;
 
    public:
        template<size_t N>
        DualPWM (const unsigned int frequency, const Pin::Mask mask1, const Pin::Mask mask2,
                 volatile unsigned int *duty1, volatile unsigned int *duty2, const uint32_t (&stack)[N])
            : Runnable(stack),
              m_period(CLKFREQ / frequency),
              m_mask1(mask1),
              m_mask2(mask2),
              m_duty1(duty1),
              m_duty2(duty2) {
        }
 
        DualPWM (const unsigned int frequency, const Pin::Mask mask1, const Pin::Mask mask2,
                 volatile unsigned int *duty1, volatile unsigned int *duty2, const uint32_t *stack,
                 const size_t stackLength)
            : Runnable(stack, stackLength),
              m_period(CLKFREQ / frequency),
              m_mask1(mask1),
              m_mask2(mask2),
              m_duty1(duty1),
              m_duty2(duty2) {
        }
 
        void run () {
            if (this->m_mask1) {
                CTRA = 0b00100 << 26 | static_cast<unsigned int>(Pin::from_mask(this->m_mask1));
                FRQA = 1;
                DIRA |= this->m_mask1;
            }
 
            if (this->m_mask2) {
                CTRB = 0b00100 << 26 | static_cast<unsigned int>(Pin::from_mask(this->m_mask2));
                FRQB = 1;
                DIRA |= this->m_mask2;
            }
 
            const register unsigned int period = this->m_period;
 
            auto timer = CNT + period;
            while (1) {
                const auto leftPhase  = *this->m_duty1 * period / MAX_DUTY;
                const auto rightPhase = *this->m_duty2 * period / MAX_DUTY;
                __asm__ volatile("neg PHSA, %0" : : "r" (leftPhase));
                __asm__ volatile("neg PHSB, %0" : : "r" (rightPhase));
                timer = waitcnt2(timer, period);
            }
        }
 
    private:
        const unsigned int    m_period;
        const Pin::Mask       m_mask1;
        const Pin::Mask       m_mask2;
        volatile unsigned int *m_duty1;
        volatile unsigned int *m_duty2;
};
 
}