DFRobot_IIC.h

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#ifndef DFROBOT_IIC_H
#define DFROBOT_IIC_H

#include "LCD.h"
#include "Driver/HD44780.h"
#include "TWI.h"
#include "Driver/PCF8574.h"

namespace LCD {
class DFRobot_IIC : public HD44780::Adapter, private PCF8574 {
public:
  DFRobot_IIC(TWI& twi, uint8_t subaddr = 7) :
    PCF8574(twi, subaddr),
    m_port()
  {}

  virtual bool setup()
  {
    ddr(0);
    return (false);
  }

  virtual void write4b(uint8_t data)
  {
    uint8_t buf[2];
    m_port.data = data;
    m_port.en = 1;
    buf[0] = m_port;
    m_port.en = 0;
    buf[1] = m_port;
    write(buf, sizeof(buf));
  }

  virtual void write8b(uint8_t data)
  {
    uint8_t buf[4];
    m_port.data = (data >> 4);
    m_port.en = 1;
    buf[0] = m_port;
    m_port.en = 0;
    buf[1] = m_port;
    m_port.data = data;
    m_port.en = 1;
    buf[2] = m_port.as_uint8;
    m_port.en = 0;
    buf[3] = m_port.as_uint8;
    write(buf, sizeof(buf));
  }

  virtual void write8n(const void* buf, size_t size)
  {
    const uint8_t* bp = (const uint8_t*) buf;
    while (size != 0) {
      uint8_t tmp[32];
      uint8_t n = (size > sizeof(tmp) / 4 ? sizeof(tmp) / 4 : size);
      size -= n;
      uint8_t m = n * 4;
      for (uint8_t i = 0; i < m;) {
        uint8_t data = *bp++;
        m_port.data = (data >> 4);
        m_port.en = 1;
        tmp[i++] = m_port;
        m_port.en = 0;
        tmp[i++] = m_port;
        m_port.data = data;
        m_port.en = 1;
        tmp[i++] = m_port;
        m_port.en = 0;
        tmp[i++] = m_port;
      }
      write(tmp, m);
    }
  }

  virtual void set_mode(uint8_t flag)
  {
    m_port.rs = flag;
  }

  virtual void set_backlight(uint8_t flag)
  {
    m_port.bt = flag;
    write(m_port.as_uint8);
  }

protected:
  union port_t {
    uint8_t as_uint8;           
    struct {
      uint8_t rs:1;             
      uint8_t rw:1;             
      uint8_t en:1;             
      uint8_t bt:1;             
      uint8_t data:4;           
    };
    operator uint8_t() { return (as_uint8); }
    port_t() { as_uint8 = 0; }
  };
  port_t m_port;                
};
};
#endif