For applications that require spinning the motor in a specific direction, prioritize knowing if the motor is coasting or spinning in the direction opposite to the intended direction of spin. MCF8315A reverse drive function acts to reverse decelerate the motor through zero speed and to accelerate after changing direction until the motor transitions into closed loop as shown in Figure 3-7.

Figure 3-7 Reverse Drive Function

MCF8315A provides an option to apply brakes and stop the motor while the motor is coasting or spinning in reverse direction and then accelerate into closed loop after changing the direction.

In applications such as ceiling fans and pumps, the requirement is to spin the motor in specific direction for desired results. For such applications, the reccomendation is to follow the below recommendations.

Step 1: Enable ISD [ISD_EN]

Step 2: Enable Motor ISD Reverse drive [RVS_DR_EN]

Step 3: Enable reverse resynchronization [RESYNC_EN]

Step 4: Enable Active brake reverse drive [ACTIVE_BRAKE_REV_DRV_EN]

Step 5: Enter the Kp coefficient [ACTIVE_BRAKE_KP] and Ki coefficient [ACTIVE_BRAKE_KI] for Active braking loop. We recommend to start with Kp coefficient [ACTIVE_BRAKE_KP] as 700 and Ki coefficient [ACTIVE_BRAKE_KI] as 100.

Step 6: Set bus current limit during active braking [ACTIVE_BRAKE_CURRENT_LIMIT]