The MC303 can be configured in sensor-less mode thanks to the comparator circuitry populated on the MC303 board or the filtered U, V, W signals coming from the MC300 power board. It supports both configurations at the same time.
When using the zero crossing signals output from comparators, ZC_U, ZC_V & ZC_W are connected to PH0, PH1 & PH2 of the ATxmega128A1.
When using the filtered U, V, W signals coming from the MC300 power board, (U_Conditioned, V_ Conditioned, W_ Conditioned) & (U_cond_neg, V_cond_neg, W_cond_neg) are connected to (PA2, PA3, PA4) & (PA0, PA1, PA7) of the ATxmega128A1.