Datasheet

TMC2300 DATASHEET (Rev. 1.02 / 2019-NOV-06) 53
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12.4 Index Signal
An active index output (enable diag_index) signals that the sine curve of motor coil A is at its positive
zero transition. This correlates to the zero point of the microstep sequence. Usually, the cosine curve
of coil B is at its maximum at the same time. Thus, the index signal is active once within each
electrical period, and corresponds to a defined position of the motor within a sequence of four
fullsteps. The index output this way allows the detection of a certain microstep pattern, and thus
helps to detect a position with more precision than a stop switch can do.
COIL A
COIL B
Current
Time
Time
Time
Current
INDEX
STEPS
0
Figure 12.3 Index signal at positive zero transition of the coil A sine curve
Hint
The index output allows precise detection of the microstep position within one electrical wave, i.e.
within a range of four fullsteps. With this, homing accuracy and reproducibility can be enhanced to
microstep accuracy, even when using an inexpensive home switch.