void writeRegister( I2C& i2c, char registerAdress, char *data, int nbBytes )
{
if( nbBytes == 0 ) return;
i2c.start();
int ack = i2c.write( MMA8452_SLAVE_ADRESS );
if( ack == 0 ) return;
ack = i2c.write( registerAdress );
if( ack == 0 ) return;
for( int i = 0; i < nbBytes; i++ )
{
if( i2c.write(data[i]) != 1 )
{
return;
}
}
i2c.stop();
}
void readRegister( I2C& i2c, int registerAdress, char buff[], size_t nbBytes )
{
if( nbBytes == 0 ) return;
i2c.start();
int ack = i2c.write( MMA8452_SLAVE_ADRESS );
if( ack == 0 ) return;
ack = i2c.write( registerAdress );
if( ack == 0 ) return;
i2c.start();
ack = i2c.write( MMA8452_SLAVE_ADRESS | 1 );
if( ack == 0 ) return;
for( int i = 0; i < nbBytes; ++i )
{
buff[ i ] = i2c.read( i == nbBytes - 1 ? 0 : 1 );
}
i2c.stop();
}
/**********************************************************
* getExtTemp - Gets the current external temperature from the sensor.
*
* @return float - The external temperature in degrees C
**********************************************************/
float TMP421::getExtTemp(void)
{
uint8_t highByte = 0x00, lowByte = 0x00;
// I2c.beginTransmission(_address);
// I2c.write(0x01);
// I2c.endTransmission();
// I2c.requestFrom((int)_address, 2); // request 2 byte from address 1001000
// while(I2c.available())
// {
// highByte = I2c.read(); // Read the first octet
// lowByte = I2c.read(); // Read the second octet
// }
I2c.write(_address, (byte) 0x01);
I2c.read(_address, (uint8_t) 2);
if(I2c.available()) {
highByte = I2c.receive();
lowByte = I2c.receive();
}
return getFraction(highByte, lowByte);
}