Datasheet
TMC220X, TMC222X DATASHEET (Rev. 1.02 / 2017-MAY-16) 34
www.trinamic.com
5.4.2 PWMCONF – Voltage PWM Mode stealthChop
0X70: PWMCONF – VOLTAGE MODE PWM STEALTHCHOP
Bit
Name
Function
Comment
31
PWM_LIM
PWM automatic scale
amplitude limit when
switching on
Limit for PWM_SCALE_AUTO when switching back from
spreadCycle to stealthChop. This value defines the upper
limit for bits 7 to 4 of the automatic current control
when switching back. It can be set to reduce the current
jerk during mode change back to stealthChop.
It does not limit PWM_GRAD or PWM_GRAD_AUTO offset.
(Default = 12)
30
29
28
27
PWM_REG
Regulation loop
gradient
User defined maximum PWM amplitude change per half
wave when using pwm_autoscale=1. (1…15):
1: 0.5 increments (slowest regulation)
2: 1 increment (default with OTP2.1=1)
3: 1.5 increments
4: 2 increments
…
8: 4 increments (default with OTP2.1=0)
...
15: 7.5 increments (fastest regulation)
26
25
24
23
-
reserved
set to 0
22
-
reserved
set to 0
21
freewheel1
Allows different
standstill modes
Stand still option when motor current setting is zero
(I_HOLD=0).
%00: Normal operation
%01: Freewheeling
%10: Coil shorted using LS drivers
%11: Coil shorted using HS drivers
20
freewheel0
19
pwm_
autograd
PWM automatic
gradient adaptation
0
Fixed value for PWM_GRAD
(PWM_GRAD_AUTO = PWM_GRAD)
1
Automatic tuning (only with pwm_autoscale=1)
PWM_GRAD_AUTO is initialized with PWM_GRAD
and becomes optimized automatically during
motion.
Preconditions
1. PWM_OFS_AUTO has been automatically
initialized. This requires standstill at IRUN for
>130ms in order to a) detect standstill b) wait >
128 chopper cycles at IRUN and c) regulate
PWM_OFS_AUTO so that
-1 < PWM_SCALE_AUTO < 1
2. Motor running and 1.5 * PWM_OFS_AUTO <
PWM_SCALE_SUM < 4* PWM_OFS_AUTO and
PWM_SCALE_SUM < 255.
Time required for tuning PWM_GRAD_AUTO
About 8 fullsteps per change of +/-1.
18
pwm_
autoscale
PWM automatic
amplitude scaling
0
User defined feed forward PWM amplitude. The
current settings IRUN and IHOLD have no influence!
The resulting PWM amplitude (limited to 0…255) is:
PWM_OFS * ((CS_ACTUAL+1) / 32)
+ PWM_GRAD * 256 / TSTEP
1
Enable automatic current control (Reset default)
17
pwm_freq1
PWM frequency
%00: f
PWM
=2/1024 f
CLK