Confused about reading data I2C

Projects Programming
8

Try this instead:

Wire.beginTransmission(0x10);
Wire.write(5);
Wire.endTransmission();

Wire.requestFrom(0x10, 2);


  while (Wire.available()) 
  {
  data = Wire.read();
  data |= Wire.read() << 8;
  }

What you'll end-up doing is:

  • Tell the slave that you want it to point to its register #5

  • then tell the slave that you want to receive 2 bytes, starting from the current position of its pointer

  • when the data are going to be available, you will read them !

I never do a "Wire.endTransmission()" after a request: maybe I'm wrong, but it has never been an issue so far ...

I noticed that you were reading the value from the slave right after requesting them: might be too fast ! That's why I use the Wire.available.

Also, keep in mind that (for example) when you write, even if you do beginTransmission + write + endTransmission, all the commands get packaged ONLY when the endTransmission is executed.

hope it help ...