EVAL6470H Datasheet, PDF (26/70 Pages) STMicroelectronics – dSPIN fully integrated microstepping motor driver with motion engine and SPI

Functional description
L6470
6.7.4
6.7.5
6.7.6
The performed motor motion is compliant to programmed speed profile boundaries
(acceleration, deceleration, minimum and maximum speed).
Note that with some speed profiles or motion commands, the deceleration phase can start
before the maximum speed is reached.
Figure 11. Motion command examples
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Stop commands
A stop command forces the motor to stop. Stop commands can be sent anytime.
The SoftStop command causes the motor to decelerate with programmed deceleration
value until the MIN_SPEED value is reached and then stops the motor keeping the rotor
position (a holding torque is applied).
The HardStop command stops the motor instantly, ignoring deceleration constraints and
keeping the rotor position (a holding torque is applied).
The SoftHiZ command causes the motor to decelerate with programmed deceleration value
until the MIN_SPEED value is reached and then forces the bridges in high impedance state
(no holding torque is present).
The HardHiZ command instantly forces the bridges into high impedance state (no holding
torque is present).
Step-clock mode
In Step-clock mode the motor motion is defined by the step-clock signal applied to the STCK
pin. At each step-clock rising edge, the motor is moved one microstep in the programmed
direction and the absolute position is consequently updated.
When the system is in Step-clock mode, the SCK_MOD flag in the STATUS register is
raised, the SPEED register is set to zero and motor status is considered stopped whatever
the STCK signal frequency (MOT_STATUS parameter in STATUS register equal to “00”).
GoUntil and ReleaseSW commands
In most applications the power-up position of the stepper motor is undefined, so an
initialization algorithm driving the motor to a known position is necessary.
The GoUntil and ReleaseSW commands can be used in combination with external switch
input (see Section 6.13) to easily initialize the motor position.
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