Hallo HaWe,
schau mal bitte hier rein:
https://allaboutmcu.wordpress.com/20...is-is-a-draft/

Auszug:

This will not work with the Wii nunchuck, even though we know its write address(which is 52 by the way, A4 in hex).
For the communication to work – after sending the write adress for the first time – “0x40” must be sent before 0.

StartI2C();
IdleI2C();
MasterWriteI2C(0xA4);
MasterWriteI2C(0x40);
MasterWriteI2C(0x00);
StopI2C();

And again for the knockoff versions of the nunchuck it’s different once more,
there are not only one but TWO handshakes this time around, the cheeky bastards:

StartI2C();
IdleI2C();
MasterWriteI2C(0xA4);
MasterWriteI2C(0xF0);
MasterWriteI2C(0x55);
StopI2C();

StartI2C();
IdleI2C();
MasterWriteI2C(0xA4);
MasterWriteI2C(0xFB);
MasterWriteI2C(0x00);
StopI2C();

Siro