How to set up a command-based communication using I2C

[DrDiettrich]

@domi1

Two issues have been found:

1. There seems to be an electrical issue with the SCL/SDA connections (but I am not sure what it is)
2. Using the Wire library on the slave never outputs something although the pin number is correct and the digital IO is working properly.

1. You miss to connect GND in your Evaluation 4. A circuit diagram were much more helpful.
   You miss that the behaviour of the SCL/SDA pins differs for normal use and use as I2C signals.

2. A slave can not output anything by itself because every transmission is started by a master.

3. Insertion of useless or redundant information is blocked for good reason, as can be seen with your rants. Why do you think that you should copy&paste I2C specification when waiting for helpful answers of experts?

Do you have more questions?