So i am trying to get a pi to i2c talk to an uno, the pi being the master. (This is not pi related, everything works fine there)
Since it took me the better part of a day to figure this out, and Arduino is such a great platform, i would like to give back by helping with the documentation problem that i uncovered.
Basically https://www.arduino.cc/en/Tutorial/MasterReader is wrong for the slave.
It should have something with OnRequest in the slave code.
Quite a good explanation i found in the forum I2C Send and Read Values - Programming Questions - Arduino Forum
I would be happy to make a pull request, as i think for other beginners this may be very helpful, and difficult as is.
Also i saw documentation on Wire.send , but the compiler complains that Wire.send does not exist.
If i can help, please let me know how.