File content as of revision 0:770879aaecd5:

#include "AM2315.h"
#include "mbed.h"


AM2315::AM2315(PinName SDA = I2C_SDA , PinName SCL = I2C_SCL ):i2c(SDA, SCL)
{
}

// I2C Temperature and Humidity Sensor AM2315
//
bool AM2315::read( )
{

  char data_write[5];
  char data_read[10];
  int i =0;
  for(i=0; i<8; i++)
    data_read[i]=0;

  // Wake up the sensor
  // write single byte twice to wake up
  // single write is not enough
  data_write[0] = 0x00;
  i2c.write(AM2315_ADDR,data_write,1,0); 
  i2c.write(AM2315_ADDR,data_write,1,0);
  
  // Read temperature and humidity register
  // send request to AM2315
  data_write[0] = AM2315_REG_READ;
  data_write[1] = 0x00;  // read from adr 0x00
  data_write[2] = 0x04;  // read 4 bytes
  i2c.write(AM2315_ADDR, data_write, 3, 0); // with stop
  
  // wait 2ms before we start to read reg
  wait_ms(2); 
  
  i2c.read(AM2315_ADDR, data_read, 8, 1);

  if (data_read[0] != AM2315_REG_READ) 
    return false;
  // check numbers of bytes read
  if (data_read[1] != 4) 
    return false; 
    
  humidity = data_read[2];
  humidity *= 256;
  humidity += data_read[3];
  humidity /= 10;
  
  celsius = data_read[4] & 0x7F;
  celsius *= 256;
  celsius += data_read[5];
  celsius /= 10;

  if (data_read[4] >> 7) 
    celsius = -(celsius);

  return true;
}