TMC2225 DATASHEET (Rev. 1.15 / 2023-FEB-16)
43
PARAMETERS RELATED TO STEALTHCHOP
Parameter Description
Setting Comment
en_spread_ General disable for use of StealthChop (register 1
cycle
GCONF). The input SPREAD is XORed to this flag. 0
Do not use StealthChop
StealthChop enabled
TPWMTHRS Specifies the upper velocity for operation in 0 …
StealthChop is disabled if
StealthChop. Entry the TSTEP reading (time 1048575 TSTEP falls TPWMTHRS
between two microsteps) when operating at the
desired threshold velocity.
PWM_LIM
Limiting value for limiting the current jerk when 0 … 15
switching from SpreadCycle to StealthChop.
Reduce the value to yield a lower current jerk.
Upper four bits of 8 bit
amplitude limit
(Default=12)
pwm_
autoscale
Enable automatic current scaling using current 0
measurement or use forward controlled velocity 1
based mode.
Forward controlled mode
Automatic scaling with
current regulator
pwm_
Enable automatic tuning of PWM_GRAD_AUTO
0
autograd
disable, use PWM_GRAD
from register instead
1
enable
PWM_FREQ
PWM frequency selection. Use the lowest setting 0
giving good results. The frequency measured at 1
each of the chopper outputs is half of the 2
effective chopper frequency fPWM.
3
fPWM=2/1024 fCLK
fPWM=2/683 fCLK
fPWM=2/512 fCLK
fPWM=2/410 fCLK
PWM_REG User defined PWM amplitude (gradient) for 1 … 15 Results in 0.5 to 7.5 steps
velocity based scaling or regulation loop gradient
when pwm_autoscale=1.
for PWM_SCALE_AUTO
regulator per fullstep
PWM_OFS User defined PWM amplitude (offset) for velocity 0 … 255 PWM_OFS=0 disables
based scaling and initialization value for automatic
tuning of PWM_OFFS_AUTO.
linear current scaling
based on current setting
PWM_GRAD User defined PWM amplitude (gradient) for 0 … 255 Reset value can be pre-
velocity based scaling and initialization value for
programmed by OTP
automatic tuning of PWM_GRAD_AUTO.
FREEWHEEL Stand still option when motor current setting is 0
Normal operation
zero (I_HOLD=0). Only available with StealthChop 1
enabled. The freewheeling option makes the 2
motor easy movable, while both coil short options 3
realize a passive brake.
Freewheeling
Coil short via LS drivers
Coil short cia HS drivers
PWM_SCALE Read back of the actual StealthChop voltage PWM -255 … (read only) Scaling value
_AUTO
scaling correction as determined by the current 255
regulator. Should regulate to a value close to 0
becomes frozen when
operating in SpreadCycle
PWM_GRAD
_AUTO
PWM_OFS
_AUTO
during tuning procedure.
Allow monitoring of the automatic tuning and 0 … 255
determination of initial values for PWM_OFS and
PWM_GRAD.
Set pwm_autoscale=0 resp. pwm_autograd=0 to
initialize from PWM_OFS and PWM_GRAD.
(read only)
TOFF
General enable for the motor driver, the actual 0
Driver off
value does not influence StealthChop
1 … 15 Driver enabled
TBL
Comparator blank time. This time needs to safely 0
16 tCLK
cover the switching event and the duration of the 1
24 tCLK
ringing on the sense resistor. Choose a setting of 2
1 or 2 for typical applications. For higher 3
capacitive loads, 3 may be required. Lower
32 tCLK
40 tCLK
settings allow StealthChop to regulate down to
lower coil current values.
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