L6482
Functional description
Doc ID 023768 Rev 1
25/73
6.7.4 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 a 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 a programmed deceleration
value until the MIN_SPEED value is reached and then forces the bridges into high
impedance state (no holding torque is present).
The HardHiZ command instantly forces the bridges into high impedance state (no holding
torque is present).
6.7.5 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 the motor status is considered stopped
regardless of the STCK signal frequency (the MOT_STATUS parameter in the STATUS
register equal to “00”).
6.7.6
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
) to easily initialize the motor position.
The GoUntil command makes the motor run at target constant speed until the SW input is
forced low (falling edge). When this event occurs, one of the following actions can be
performed:
●
ABS_POS register is set to zero (home position) and the motor decelerates to zero
speed (as a SoftStop command)
●
ABS_POS register value is stored in the MARK register and the motor decelerates to
zero speed (as a SoftStop command).
If the SW_MODE bit of the CONFIG register is set to ‘0’, the motor does not decelerate but
it immediately stops (as a HardStop command).
The ReleaseSW command makes the motor run at a programmed minimum speed until the
SW input is forced high (rising edge). When this event occurs, one of the following actions
can be performed:
●
ABS_POS register is set to zero (home position) and the motor immediately stops (as a
HardStop command)
●
ABS_POS register value is stored in the MARK register and the motor immediately
stops (as a HardStop command).
If the programmed minimum speed is less than 5 step/s, the motor is driven at 5 step/s.
