Texas Instruments DRV8846, User Manual

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VINT
VREF (VREF _ slider 4)
4095
= ´ ´
VREF
I TORQUE StepModifier
FS
6.6 RISENSE
= ´ ´
´
Introduction
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2.3 Jumpers
There are no jumpers on the DRV8846EVM module.
2.4 Motor Outputs
Two motor connectors are provided. Connectors J2 and J3 are available as shown in Figure 1 .
2.5 Operation of the EVM
Use the following steps to operate the EVM.
1. Install the drivers and GUI. Refer to Appendix A at the end of this document for instructions.
2. Connect the wires of the stepper motor to terminals AOUT1, AOUT2, BOUT1, and BOUT2.
3. Connect the VM power supply but do not apply power at this step.
4. Connect the USB between the PC and the EVM. Open the GUI by selecting the launcher.exe file. It
may take up to 15 seconds to establish connection.
(a) Once the USB connection is established, the Status LED will begin to blink.
5. Apply 12 V to the VM and GND connections.
6. Configure the current settings, step and decay modes, torque, and pwm off time as desired as shown
in the following image:
The current is calculated using the VREF slider, the Sense resistor value, the Torque setting, and the
Step mode setting using the formula.
(1)
Where StepModifier is 0.71 for full step and 1.0 for other STEP MODE settings
The 12-bit DAC channel 0 is connected to the DRV8846 analog input VREF. Changing the DAC digital
value from 0 to 4092 in steps of 4, changes the analog voltage at the VREF pin from 0 V to VINT V.
See
Equation 2 .
(2)
Where VINT is the output of the DRV8846 pin and VREF_slider is the slider value from 0 to 1023.
4 DRV8846 Evaluation Module SLLU203A – June 2014 – Revised March 2015
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