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STEPMO_EVK_20x
Evaluation Board Manual
EUDC59-U-002 - Rev. 1.3
MTH
Voltage /
V
Current Decay
Mode
Explanation
0.0
– 0.3
Slow
Any voltage in
the given range will result in the same “slow” decay mode.
Typically just pull to GND to activate.
0.3
– 0.4
Transition
region
Do not set the MTH voltage in this region because the resulting decay mode is
not guaranteed.
0.4
– 1.0
Mixed
The mixture of “slow” and “fast” decay is not fixed in this region. The optimum
setting can be tuned by applying an analog voltage to the MTH terminal. By
jumper configuration (see EVK manual) just one predefined setting ( ~ 0.75V) is
provided. If a different Mixed Mode MTH voltage is desired the voltage divider
built by R9, R10, R11 must be adjusted.
1.0
– 1.5
Transition
region
Do not set the MTH voltage in this region because the resulting decay mode is
not guaranteed.
1.5
– 3.5
Fast
Any voltage in the
given range will result in the same “fast” decay mode. Simply
pull to 3.3V logic pin or use a 1:1 voltage divider for 5V logic.
Table 7: Current decay mode explanations
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Supply and Motor Connection
The STEPMO_EVK_20x allows the connection of a 4-wire bipolar or 5-wire unipolar stepper motor to the screw terminal J7/J8. The
outputs V1A and V1B belong to one phase of the motor while V2A and V2B to the other. If the motor spins clockwise when it should
go counter clockwise the polarity of one phase should be reversed, i.e. the wiring position of one phase should be swapped (either
V1A with V1B OR V2A with V2B not both).
The connection of a bipolar motor is depicted in Figure 4. In case of a unipolar motor the additional common mode wire(s) are
connected to the GND middle pin.
The power supply is connected to screw terminal J6. Although the EVK is equipped with a reverse power supply protection care
should be taken about the polarity of the supply.
To meet the requirements from electromagnetic compatibility (EMC) all connected cables must not exceed a length of 3m.
Note:
In case of stacking two EVK Shields in Master/Slave configuration only the Master Shield must be supplied by the
external power supply. The Slave Shield is powered via terminal J4 with the same applied voltage.
When applying power to the Shield please double check the EVK model version you are using and take care to stay
within the rated power supply limits as listed in Table 1. Operating the EVK over the given supply voltage ratings may
permanently damage the EVK.
Figure 4: Connection of Stepper Motor and Power Supply
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