PCF8574.cpp

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#include "PCF8574.hh"

bool
PCF8574::data_direction(uint8_t ddr)
{
  m_ddr = ddr;
  m_port |= m_ddr;
  twi.acquire(this);
  int res = twi.write(&m_port, sizeof(m_port));
  twi.release();
  return (res == sizeof(m_port));
}

uint8_t
PCF8574::read()
{
  uint8_t res;
  twi.acquire(this);
  twi.read(&res, sizeof(res));
  twi.release();
  return (res & m_ddr);
}

bool
PCF8574::write(uint8_t pin, uint8_t value)
{
  uint8_t mask = _BV(pin & PIN_MASK);
  if (value)
    m_port |= mask;
  else
    m_port &= ~mask;
  twi.acquire(this);
  int res = twi.write(&m_port, sizeof(m_port));
  twi.release();
  return (res == sizeof(m_port));
}

bool
PCF8574::write(uint8_t value)
{
  twi.acquire(this);
  m_port = value | m_ddr;
  int res = twi.write(&m_port, sizeof(m_port));
  twi.release();
  return (res == sizeof(m_port));
}

bool
PCF8574::write(void* buf, size_t size)
{
  twi.acquire(this);
  uint8_t* bp = (uint8_t*) buf;
  size_t n = size;
  while (n--) *bp++ |= m_ddr;
  int res = twi.write(buf, size);
  twi.release();
  return (res == (int) size);
}