SRPO.hh

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#ifndef COSA_SRPO_HH
#define COSA_SRPO_HH

#include "Cosa/SPI.hh"

template<uint8_t N>
class SRPO : public SPI::Driver {
public:
  static const uint8_t PINS = N * CHARBITS;

#if !defined(BOARD_ATTINY)
  SRPO(Board::DigitalPin cs = Board::D10,
       SPI::Clock rate = SPI::DEFAULT_CLOCK) :
    SPI::Driver(cs, SPI::PULSE_HIGH, rate)
  {
    clear();
    update();
  }
#else
  SRPO(Board::DigitalPin cs = Board::D3,
       SPI::Clock rate = SPI::DEFAULT_CLOCK) :
    SPI::Driver(cs, SPI::PULSE_HIGH, rate)
  {
    clear();
    update();
  }
#endif

  bool is_set(uint8_t pin)
    __attribute__((always_inline))
  {
    uint8_t ix = (pin >> 3);
    return ((m_port[ix] & _BV(pin & 0x7)) != 0);
  }

  void is_clear(uint8_t pin)
    __attribute__((always_inline))
  {
    uint8_t ix = (pin >> 3);
    return ((m_port[ix] & _BV(pin & 0x7)) == 0);
  }

  void set(uint8_t pin)
    __attribute__((always_inline))
  {
    uint8_t ix = (pin >> 3);
    m_port[ix] |= _BV(pin & 0x7);
  }

  void clear(uint8_t pin)
    __attribute__((always_inline))
  {
    uint8_t ix = (pin >> 3);
    m_port[ix] &= ~_BV(pin & 0x7);
  }

  void toggle(uint8_t pin)
    __attribute__((always_inline))
  {
    if (is_set(pin))
      clear(pin);
    else
      set(pin);
  }

  void set()
    __attribute__((always_inline))
  {
    memset(m_port, 0xff, N);
  }

  void clear()
    __attribute__((always_inline))
  {
    memset(m_port, 0, N);
  }

  void update()
  {
    spi.acquire(this);
      spi.begin();
        uint8_t ix = N - 1;
        spi.transfer_start(m_port[ix]);
        while (ix--) {
          uint8_t data = m_port[ix];
          spi.transfer_await();
          spi.transfer_start(data);
        }
        spi.transfer_await();
      spi.end();
    spi.release();
  }

  class OutputPin {
  public:
    OutputPin(SRPO<N>* srpo, uint8_t pin) :
      m_srpo(srpo),
      m_pin(pin)
    {
    }

    void set()
      __attribute__((always_inline))
    {
      m_srpo->set(m_pin);
    }

    void clear()
      __attribute__((always_inline))
    {
      m_srpo->clear(m_pin);
    }

    void toggle()
      __attribute__((always_inline))
    {
      m_srpo->toggle(m_pin);
    }

  protected:
    SRPO<N>* m_srpo;
    const uint8_t m_pin;
  };

protected:
  uint8_t m_port[N];
};
#endif