4 Basic Controls
The goal of this section is to provide customers tuning guidance to conform to use-case and explore various
features in the device.
Note, the user is expected to skip the subsection use-cases and scenarios that do not apply to the system or end
equipment.
4.1 Device and Pin Configuration
4.1.1 Power Saver or Sleep Mode for Battery Operated Applications
MCF8316A can be configured to be in Sleep mode or Standby mode. For applications that operate using
batteries, it is important to save power while the device is not spinning the motor.
MCF8316A enters sleep mode when speed input is held continuously below the speed threshold for
SLEEP_ENTRY_TIME.
In sleep mode, all motor outputs are disabled, the charge pump is disabled, the AVDD regulator is disabled,
and the serial communication bus is disabled. MCF8316A can be configured to be in sleep mode by configuring
register bits DEV_MODE. Please note that in Sleep mode, GUI will loose connectivity as there will be no I2C
communication.
4.1.2 Direction and Brake Pin Override
Direction and Brake pin override will be helpful in applications where it is not intended for the users to affect the
direction and brake pins in the device. In such cases, it is recommended to override both pins and configure
them via EEPROM.
Direction pin in MCF8316A can be overwritten by configuring DIR_INPUT. Configuring DIR_INPUT to 01b will
overwrite Hardware pin to clockwise rotation if motor phases A, B and C are connected to OUTA, OUTB
and OUTC respectively. Commutation sequence in clockwise direction will be OUTA-OUTB-OUTC. Configuring
DIR_INPUT to 10b will overwrite Hardware pin to anti-clockwise rotation if motor phases A, B and C are
connected to OUTA, OUTB and OUTC respectively. Commutation sequence in anti-clockwise direction will be
OUTA-OUTC-OUTB.
BRAKE pin in MCF8316A can be overwritten by configuring BRAKE_INPUT. Configuring BRAKE_INPUT
to 01b will overwrite Hardware pin to low side brake/Align according to BRAKE_PIN_MODE. Configuring
BRAKE_INPUT to 10b will overwrite Hardware pin and not low side brake/align.
In Low side braking mode, all the LS FETs will be turned ON. In Align braking mode, MCF8316A aligns a motor
by injecting dc current through a particular phase pattern.
4.2 System Level Configuration
4.2.1 Tracking Motor Speed Feedback in Real Time
MCF8316A device provides information about the motor speed through the frequency generator (FG) pin,
which is also known as a TACH (tachometer) out. In MCF8316A, the FG pin behavior is configured through
FG_CONFIG. Configure FG_SEL to output FG signal only in closed loop, both open loop and closed loop, or
only in open loop for the first try. Configure FG_DIV to number of motor poles so that the FG output matches the
motor mechanical speed in Hz.
When FG_CONFIG is configured to 0 (FG active as long as motor is driven), the FG output is active as long as
MCF8316A is driving the motor. FG will not be active during a motor stop and coasting condition. In this mode,
FG is released high when MCF8316A enters sleep or standby mode. This mode is useful in applications that
require real time motor speed information as long as MCF is driving the motor.
When FG_CONFIG is configured to 1 (FG active till BEMF drops below FG_BEMF_THR), MCF8316A provides
FG output until BEMF falls below FG_BEMF_THR. The FG output will continue to indicate motor speed even if
the motor is not being actively driven. This mode is useful in applications that require motor speed information
above a certain speed, and rotor motion information during the coast and braking conditions.
Basic Controls
12
MCF8316A Tuning Guide
SLLU335A – AUGUST 2021 – REVISED JANUARY 2022
Copyright © 2022 Texas Instruments Incorporated
