MCP23008.hh

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#ifndef COSA_MCP23008_HH
#define COSA_MCP23008_HH

#include "Cosa/TWI.hh"

class MCP23008 : private TWI::Driver {
public:
  enum InterruptMode {
    DISABLE = 0,                
    ON_CHANGE = 1,              
    ON_FALLING = 2,             
    ON_RISING = 3               
  } __attribute__((packed));

  MCP23008(uint8_t subaddr = 0) :
    TWI::Driver(0x20 | (subaddr & SUBADDR_MASK)),
    m_iodir(0xff),
    m_gpinten(0),
    m_defval(0),
    m_intcon(0),
    m_gppu(0),
    m_olat(0)
  {}

  bool begin();

  bool data_direction(uint8_t iodir);

  bool pullup(uint8_t gppu);

  bool input_pin(uint8_t pin)
    __attribute__((always_inline))
  {
    return (data_direction(m_iodir | _BV(pin & PIN_MASK)));
  }

  bool pullup_pin(uint8_t pin)
    __attribute__((always_inline))
  {
    return (pullup(m_gppu | _BV(pin & PIN_MASK)));
  }

  bool interrupt_pin(uint8_t pin, InterruptMode mode);

  bool output_pin(uint8_t pin)
    __attribute__((always_inline))
  {
    return (data_direction(m_iodir & ~_BV(pin & PIN_MASK)));
  }

  bool read_pin(uint8_t pin)
    __attribute__((always_inline))
  {
    return ((read() & _BV(pin & PIN_MASK)) != 0);
  }

  bool write_pin(uint8_t pin, uint8_t value)
  __attribute__((always_inline))
  {
    uint8_t mask = _BV(pin & PIN_MASK);
    if (value)
      m_olat |= mask;
    else
      m_olat &= ~mask;
    return (write(m_olat));
  }

  uint8_t read();

  bool read(void* buf, size_t size);

  bool write(uint8_t value);

  bool write(void* buf, size_t size);

protected:
  static const uint8_t SUBADDR_MASK = 0x07;

  static const uint8_t PIN_MASK = 0x07;

  enum {
    IODIR = 0x00,               
    IPOL = 0x01,                
    GPINTEN = 0x02,             
    DEFVAL = 0x03,              
    INTCON = 0x04,              
    IOCON = 0x05,               
    GPPU = 0x06,                
    INTF = 0x07,                
    INTCAP = 0x08,              
    GPIO = 0x09,                
    OLAT = 0x0a,                
    REG_MAX = 0x0b              
  } __attribute__((packed));

  enum {
    INTPOL = 1,                 
    ODR = 2,                    
    HAEN = 3,                   
    DISSLW = 4,                 
    SEQOP = 5                   
  } __attribute__((packed));

  uint8_t m_iodir;

  uint8_t m_gpinten;

  uint8_t m_defval;

  uint8_t m_intcon;

  uint8_t m_gppu;

  uint8_t m_olat;

  uint8_t m_reg;
};
#endif