Datasheet

TMC220X, TMC222X DATASHEET (Rev. 1.02 / 2017-MAY-16) 46
www.trinamic.com
PARAMETERS RELATED TO STEALTHCHOP
Parameter
Description
Setting
Comment
en_spread_
cycle
General disable for use of stealthChop (register
GCONF). The input SPREAD is XORed to this flag.
1
Do not use stealthChop
0
stealthChop enabled
TPWMTHRS
Specifies the upper velocity for operation in
stealthChop. Entry the TSTEP reading (time
between two microsteps) when operating at the
desired threshold velocity.
0 …
1048575
stealthChop is disabled if
TSTEP falls TPWMTHRS
PWM_LIM
Limiting value for limiting the current jerk when
switching from spreadCycle to stealthChop. Reduce
the value to yield a lower current jerk.
0 … 15
Upper four bits of 8 bit
amplitude limit
(Default=12)
pwm_
autoscale
Enable automatic current scaling using current
measurement or use forward controlled velocity
based mode.
0
Forward controlled mode
1
Automatic scaling with
current regulator
pwm_
autograd
Enable automatic tuning of PWM_GRAD_AUTO
0
disable, use PWM_GRAD
from register instead
1
enable
PWM_FREQ
PWM frequency selection. Use the lowest setting
giving good results. The frequency measured at
each of the chopper outputs is half of the
effective chopper frequency f
PWM
.
0
f
PWM
=2/1024 f
CLK
1
f
PWM
=2/683 f
CLK
2
f
PWM
=2/512 f
CLK
3
f
PWM
=2/410 f
CLK
PWM_REG
User defined PWM amplitude (gradient) for
velocity based scaling or regulation loop gradient
when pwm_autoscale=1.
1 … 15
Results in 0.5 to 7.5 steps
for PWM_SCALE_AUTO
regulator per fullstep
PWM_OFS
User defined PWM amplitude (offset) for velocity
based scaling and initialization value for automatic
tuning of PWM_OFFS_AUTO.
0 … 255
PWM_OFS=0 disables
linear current scaling
based on current setting
PWM_GRAD
User defined PWM amplitude (gradient) for
velocity based scaling and initialization value for
automatic tuning of PWM_GRAD_AUTO.
0 … 255
Reset value can be pre-
programmed by OTP
FREEWHEEL
Stand still option when motor current setting is
zero (I_HOLD=0). Only available with stealthChop
enabled. The freewheeling option makes the
motor easy movable, while both coil short options
realize a passive brake.
0
Normal operation
1
Freewheeling
2
Coil short via LS drivers
3
Coil short cia HS drivers
PWM_SCALE
_AUTO
Read back of the actual stealthChop voltage PWM
scaling correction as determined by the current
regulator.
-255 …
255
(read only) Scaling value
becomes frozen when
operating in spreadCycle
PWM_SCALE
_AUTO
PWM_OFS
_AUTO
Allow monitoring of the automatic tuning and
determination of initial values for PWM_OFS and
PWM_GRAD.
0 … 255
(read only)
TOFF
General enable for the motor driver, the actual
value does not influence stealthChop
0
Driver off
1 … 15
Driver enabled
TBL
Comparator blank time. This time needs to safely
cover the switching event and the duration of the
ringing on the sense resistor. Choose a setting of
1 or 2 for typical applications. For higher
capacitive loads, 3 may be required. Lower
settings allow stealthChop to regulate down to
lower coil current values.
0
16 t
CLK
1
24 t
CLK
2
32 t
CLK
3
40 t
CLK