No need to wait after Wire.requestFrom()

[Koepel]

After the Wire.requestFrom() there is no need to wait for something and the timeout with millis() is not needed.

When the Wire.requestFrom() returns, the I2C transaction has completely finished and the received data is waiting in a buffer in the Wire library.

After the Wire.requestFrom() you may call Wire.available() to test if the same number of bytes was received as was requested.

[Risele]

You mean, that I could change
while ((Wire.available()<6) && ((millis() - WaitingBeginTime) < _TimeoutMillisec))
{
//Do nothing, just wait
}
if ((millis() - WaitingBeginTime) < _TimeoutMillisec)
{
//....
}
//...

just for
if (Wire.available()<6)
{
//....
}
?

[Koepel]

Yes, I think so.

To me, it makes more sense to test for 6 bytes. If 6 bytes are requested, and 6 bytes are received, then everything is okay. You have to fill in the "..." and the "???".

  Wire.requestFrom(_Address, (uint8_t)6);
  if (Wire.available() == 6)
  {
    uint8_t data[6];
    for (uint8_t i = 0; i<6; i++)
    {
      data[i] = Wire.read();
    }
    if ((CRC8(data[0],data[1],data[2])) && (CRC8(data[3],data[4],data[5])))
    {
      ...
    }
  }
  else
  {
    _Error = ???;         // an error on the I2C bus
  }

The situation that Wire.available() does not return 6 bytes is very rare. It could be a problem on the I2C bus, or it could be a collision in a multi-master I2C bus. However, many problems on the bus are not detected and with some problems the Wire library might crash-halt and stop the sketch.