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 Real time variable tracking
MCT8316A has two 12-bit DAC which outputs analog voltage equivalent of digital variables on DACOUT1 and
DACOUT2 pins with resolution of 12 bits and max voltage of 3V. Signals available on DACOUT pins can be
used for tuning speed controller or other driver configuration or bus current monitoring. Check algorithm variable
registers in datasheet for list of all available algorithm variables.
The address for variables for DACOUT1 and DACOUT2 is configured using register bits DACOUT1_VAR_ADDR
and DACOUT2_VAR_ADDR. This is useful in applications which require tracking algorithm variables in real time
without having any delay from the communication bus. Pin 37 and 38 should be configured as DACOUT1 and
DACOUT2.
For example, if the user wants to read the motor speed from pin 37, configure pin 37 as DACOUT1 and program
the motor speed register address (0x5AA) in Hex in [DACOUT1_VAR_ADDR].
Pin 38 [DAC_SOX_CONFIG] can be configured to either output DACOUT2 or CSA outputs SOA, SOB or SOC.
Note: Pin 37 and 38 can either be used as DACOUT1 and DACOUT2 for real time variable tracking or as X1 and
X2 for external clock source. Both functionalities cannot be used together.
4.1.2 Power saver or sleep mode for battery operated applications
MCT8316A 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.
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. MCT8316A can be configured to be in sleep mode by configuring
register bits DEV_MODE. Please note that in Sleep mode, GUI will lose connectivity as there will be no I2C
communication.
4.1.3 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 MCT8316A 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 MCT8316A can be overwritten by configuring BRAKE_INPUT. Configuring BRAKE_INPUT to 01b
will overwrite Hardware pin to active braking. Configuring BRAKE_INPUT to 10b will overwrite Hardware pin and
disable brake functionality.
4.1.4 Improving speed accuracy with external clock source
If MCT8316A does not meet speed accuracy requirements then MCT8316A provides options to support crystal
oscillator or external clock reference. Please follow below recommendations to improve speed accuracy in
MCT8316A.
Option 1: Crystal oscillator
Basic Controls
12
MCT8316A Tuning Guide
SLLU336 – MAY 2021
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