I2C Slave not working

[noscene]

need add this to sketch because interupt tables different on samd21/samd51

void SERCOM2_0_Handler() { Wire.onService(); }
void SERCOM2_1_Handler() { Wire.onService(); }
void SERCOM2_2_Handler() { Wire.onService(); }
void SERCOM2_3_Handler() { Wire.onService(); }