Datasheet

TMC2130 DATASHEET (Rev. 1.09 / 2017-MAY-15) 76
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18.3.2 DCO Interface to Motion Controller
DCEN enables dcStep. It is up to the connected motion controller to enable dcStep either, once a
minimum step velocity is exceeded within the motion ramp, or to use the automatic threshold
VDCMIN for dcStep enable.
The STEP/DIR interface works in microstep resolution, even if the internal step execution is based on
fullstep. This way, no switching to a different mode of operation is required within the motion
controller. The dcStep output DCO signals if the motor is ready for the next step based on the dcStep
measurement of the motor. If the motor has not yet mechanically taken the last step, this step cannot
be executed, and the driver stops automatically before execution of the next fullstep. This situation is
signaled by DCO. The external motion controller shall stop step generation if DCOUT is low and wait
until it becomes high again. Figure 18.5 shows this principle. The driver buffers steps during the
waiting period up to the number of microstep setting minus one. In case, DCOUT does not go high
within the lower step limit time e.g. due to a severe motor overload, a step can be enforced: override
the stop status by a long STEP pulse with min. 1024 system clocks length. When using internal clock,
a pulse length of minimum 125µs is recommended.
µC or Motion
Controller
TMC2130
STEP
DCO
DIR
DCEN
DCIN
Optional axis
synchronization
Figure 18.4 Full signal interconnection for dcStep
+IMAX
-IMAX
0
Phase
Current
(one phase
shown)
STEP
DCEN
DCO
STEP_FILT_INTERN
∆2
INTCOM
∆2 ∆2 ∆2 ∆2 ∆2 ∆2
DC_OUT TIMEOUT
(in controller)
Long pulse = override motor block
situation
TIMOUT
counter in
controller
Theoretical sine
wave
corresponding to
fullstep pattern
Increasing mechanical load forces slower motion
∆2 = MRES (number of microsteps per fullstep)
Figure 18.5 DCO Interface to motion controller – step generator stops when DCO is asserted