MCF8315C provides two modes of controlling the motor based on
SPEED_LOOP_DIS setting,
- Speed control: In speed
control mode (SPEED_LOOP_DIS = 0b), the speed of the motor is controlled
according to the input reference using a closed loop PI control .
- Current control: In current
control mode (SPEED_LOOP_DIS = 1b), the torque controlling current
(Iq) is controlled according to the input reference using a
closed loop PI control.
MCF8315C offers four methods of directly controlling the input
reference of the motor. The input reference source is configured by SPEED_MODE.
The input reference source can be
provided in one of the following four ways,
- Analog input on SPEED pin by
varying amplitude of input signal (SPEED_MODE = 00b)
- PWM input on SPEED pin by varying
duty cycle of input signal (SPEED_MODE = 01b)
- Over I2C by
configuring DIGITAL_SPEED_CTRL register (SPEED_MODE =
10b)
- Frequency input on SPEED pin by
varying frequency of input signal (SPEED_MODE = 11b)
The
signal path from SPEED pin input (or I2C based speed input) to motor
control reference (SPEED_REF or CURRENT_REF in Figure 6-33) is as shown in Figure 6-14.
Note: When SPEED pin input is set to
zero, MCF8315C will take up to SLEEP_ENTRY_TIME
before starting the motor stop operation.