After working successfully with the MKRZero and I2C a long time, I now have the problem that apparently Wire.onReceive on the slave is no longer triggered.
I verified the problem with a playground of two connected MKRZero and the simple code examples taken from the Wire library. The result is exactly the same, Master sends, but it stays with a NACK.
I tried both IDE 1.8.9 and 1.8.10.
Code.pdf (36.3 KB)