Motor Control Signals
When BRAKE pin is driven
'High', MCF8315A
enters brake state. Brake state can be
configured to either low side braking (see Low-Side Braking) or align brake (see Align Braking) through BRAKE_PIN_MODE.MCF8315A
decreases output speed to value defined by BRAKE_SPEED_THRESHOLD before entering brake state. As long as
BRAKE is driven 'High', MCF8315A
stays in brake state. Brake pin input can be overwritten by configuring
BRAKE_INPUT over the I2C interface.
- The DIR pin decides the direction of motor spin;
when driven 'High', the sequence is OUT A →
OUT B → OUT C, and when driven 'Low', the sequence is OUT A → OUT C → OUT B. DIR pin input can
be overwritten by configuring DIR_INPUT over the I2C interface.
- When DRVOFF pin is driven 'High',
MCF8315A
stops driving the motor by turning OFF all MOSFETs (coast state). When DRVOFF is
driven 'Low', MCF8315A
returns to normal state of operation, as if it was restarting the motor (see
DRVOFF Functionality). DRVOFF does not cause the device to go to sleep or standby
mode; the digital core is still active. Entry and exit from sleep or standby
condition is controlled by SPEED pin.
- SPEED/WAKE pin is used to control motor speed and
to wake up MCF8315A
from sleep mode. SPEED pin can be configured to accept PWM, frequency or analog
input signals. It is used to enter and exit from sleep and standby mode (see
Table 7-6).
External Oscillator and Watchdog Signals
Output Signals
- DACOUT1 outputs internal variable defined by address in
register DACOUT1_VAR_ADDR. DACOUT1 is refreshed every PWM cycle (see DAC outputs).
- DACOUT2 outputs internal
variable defined by address in register DACOUT2_VAR_ADDR. DACOUT2 is
refreshed every PWM cycle (see DAC outputs).
- FG pin provides pulses which are proportional to motor
speed (see FG Configuration).
- nFAULT (active low) pin provides fault status in device or
motor operation.
- ALARM pin, if enabled using
ALARM_PIN_EN, provides fault status in device or motor operation. When ALARM
pin is enabled, report only faults are reported only on ALARM pin (as logic
high) and not reported on nFAULT pin (as logic low). When ALARM pin is
enabled, actionable faults are reported on ALARM pin (as logic high) as well
as on nFAULT pin (as logic low). When ALARM pin is disabled, it is in Hi-Z
state and all faults (actionable and report only) are reported on nFAULT as
logic low. ALARM pin should be left floating when unused/disabled.
- SOX pin provides the output of one of the current sense
amplifiers.