Texas Instruments DRV8834EVM User manual

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DRV8834 Evaluation Module
User's Guide
SLVU701B–March 2012–Revised July 2019
DRV8834 Evaluation Module
This document is provided as a supplement to the DRV8834 datasheet. It details the hardware
implementation of the DRV8834 customer evaluation module (EVM).
Contents
1 Introduction ................................................................................................................... 2
2 Block Diagram................................................................................................................ 2
2.1 Power Connectors.................................................................................................. 3
2.2 Test Stakes.......................................................................................................... 3
2.3 Jumpers.............................................................................................................. 4
2.4 Switches ............................................................................................................. 4
2.5 Motor Outputs ....................................................................................................... 4
3 GUI Software Installation .................................................................................................. 4
3.1 System Requirements.............................................................................................. 4
3.2 Installation Procedure .............................................................................................. 4
4 The Windows Application ................................................................................................. 15
4.1 Dual H Bridge Mode .............................................................................................. 16
4.2 The CONFIG Control Signal..................................................................................... 18
4.3 Configuring Switches ............................................................................................. 18
4.4 Menu Options ..................................................................................................... 19
4.5 DRV8834 GPIO Control Signals ................................................................................ 20
4.6 Updating DAC Output for Current Control (VREF) ........................................................... 20
4.7 Stepper Control.................................................................................................... 21
4.8 Move Steps Frame................................................................................................ 22
5 Schematics and Bill of Materials ......................................................................................... 24
5.1 Schematics......................................................................................................... 24
5.2 Bill of Materials .................................................................................................... 26
Trademarks
Windows is a registered trademark of Microsoft corporation.
All other trademarks are the property of their respective owners.

VM Power
DRV8834
Motor Outputs
USB
Conn USB Chip
MSP430
BDECAY
Config
Switch
3.3V LDO
Test
Points
ADECAY
Config
Switch
BVREF
Config
Switch
AVREF
Config
Switch
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1 Introduction
The DRV8834 customer EVM is a platform revolving around the DRV8834, a low voltage dual H-bridge
driver and highly configurable power stage. This device has been optimized to drive either two brushed
DC motors, a single bipolar stepper with up to 32 degrees of internally generated microstepping, or a
single bipolar stepper with high resolution externally generated microstepping. In this EVM, high resolution
is meant to imply 512 degrees of microstepping, but higher resolution, as given by any given DAC
resource, can be implemented.
The EVM houses an MSP430 microcontroller and an USB interface chip. The USB chip allows for serial
communications from a PC computer where a Windows®application is used to schedule serial
commands. These commands can be used to control each of the device’s signals, or control both devices
at the same time to drive a stepper motor.
The microcontroller firmware operates in one of three modes. Each of the three modes can be selected
through the Windows application by choosing the respective operation TAB. The three modes are:
• Dual H-Bridge with independent current control and PWM control on the ENABLE and PHASE lines.
• Internal indexer microstepping driver capable of supplying up to 32 degrees of microstepping to a
single bipolar stepper motor.
• Dual H-Bridge configured to supply up to 512 degrees of microstepping to a single bipolar stepper
motor.
This user's guide details the operation of the EVM in any of the three modes, as well as the hardware
configurability of the evaluation module.
2 Block Diagram

M0/APHASE
nSLEEP
nFAULT
BDECAY
DIR/BPHASE
STEP/BENBL
CONFIG
M1
GND
AVREF
J3
ADECAY
nENBL /AENBL
BVREF
VDD
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2.1 Power Connectors
The DRV8834EVM offers access to VM (motor voltage) power rail via a terminal block (J1). A set of test
clips in parallel with the terminal block allows for the monitoring of the input power rail.
User must apply VM according to datasheet recommended parameters.
NOTE: VDD for logic and microcontroller is derived from a provided 3.3-V regulator stepped down
from the VM input voltage.
2.2 Test Stakes
A 0.100 inch pitch header connector (J3) is used to provide access to every device signal in the event a
different microcontroller is to be employed. To disconnect the internal MSP430 microcontroller, simply
remove power to this resource by removing the shunt from the JP3 jumper.
Figure 1. J3 Connector

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2.3 Jumpers
The DRV8834EVM module contains three 2-pin jumpers which the user can remove in order modify
certain aspects of configuration.
• JP1: Place a shunt to enable the D1 LED signaling of any fault occurrence.
• JP3: Place a shunt to allow 3.3-V supply to the microcontroller. Remove the shunt to disable MSP430
microcontroller and use external microcontroller of choice.
• JP4: Place a shunt to provide VM power to the LDO. Remove to disconnect all VM loading except
DRV8834 device.
2.4 Switches
A series of switches allow the proper selection of analog input to configure the reference voltage and
decay set points.
Table 1. Switches
SWITCH NAME DESCRIPTION
BDECAY SEL Selects Decay B source to be MSP430 GPIO (only HI or LO), externally
supplied or derived from the R1 potentiometer.
ADECAY SEL Selects Decay A source to be MSP430 GPIO (only HI or LO), externally
supplied or derived from the R2 potentiometer.
BVREF SEL Selects Reference Voltage B source to be same as VREFA (used on internal indexer mode), MSP430 DAC, externally supplied or derived from the R7
potentiometer.
AVREF SEL Selects Reference Voltage A source to be MSP430 DAC, externally supplied or
derived from the R6 potentiometer.
Each switch position is properly documented on the board’s top layer overlay silk screen.
2.5 Motor Outputs
There are two ways of connecting the dual brushed DC motor or the single bipolar stepper motor into the
DRV8834 evaluation module: four pin header (J2) or four position terminal block (J4).
3 GUI Software Installation
The following section explains the location of files and the procedure for installing the software correctly.
NOTE: Ensure that no USB connections are made to the EVM until the installation is completed.
The installer will also install LabVIEW RTE 2014 and FTDI Driver, along with the GUI.
3.1 System Requirements
• Supported OS – Windows 7 (32 Bit, 64 Bit). The window text size should be Smaller-100% (Default)
• Recommended RAM - 4 GB or higher
• Recommended CPU Operating Speed – 3.3 GHz or higher
3.2 Installation Procedure
The following procedure helps you install the DRV8834 GUI
1. Double click on the Setup_DRV8834_EVM.exe as shown in Figure 2.

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Figure 2. Setup_DRV8834_EVM.exe
2. The screen shown in Figure 3 appears, indicating installer initialization. Click the Next button.
Figure 3. Installation Initialization
3. In the newly open installation pop-up window, click Next. The license agreement will be displayed.
Please, read through it carefully and enable the "I Accept the Agreement" radio button and press Next.

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Figure 4. License Agreement
4. A screen as shown in Figure 5 appears, displaying the license agreement of National Instruments.
Please read through the agreement carefully and enable the “I Accept the License Agreement” radio
button and press the Next button.
Figure 5. NI License Agreement
5. Set the default directory for the GUI Installation and click Next.

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Figure 6. Installation Directory Screen
NOTE: It is highly recommended to keep the default values as provided in the installer.
6. A screen as shown in Figure 7 appears. This screen is to select the components to install. Select the
Components to Install and Click Next to continue installation. The LabVIEW RTE component checks
out if the LabVIEW RTE 2014 is already installed on the PC.
Figure 7. Component Selection
7. If LabVIEW RTE is selected as a component to install, a screen appears as shown in Figure 8.
Configure the proxy settings as required. This screen is to download the LabVIEW RTE 2014 from
ni.com, Click Next to continue the installation.

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Figure 8. Configure Proxy
8. A screen as shown in Figure 9appears. Click Next to begin the installation.
Figure 9. Ready to Install
9. If the LabVIEW RTE 2014 is selected as a component to install, LabVIEW RTE downloads and
performs a silent mode installation.

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Figure 10. Downloading RTE
10. Once the download completes, LabVIEW begins with the self-extraction as shown in Figure 11.
Figure 11. LabVIEW RTE Self Extraction
11. A screen appears as shown in Figure 12. It initializes the LabVIEW RTE Installation.

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Figure 12. LabVIEW RTE Installation Initialization
12. A display as shown in Figure 13 appears which indicates the progress of LabVIEW RTE installation.

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Figure 13. Installation of LabVIEW RTE in Progress
13. Once the LabVIEW RTE 2014 is installed, DRV 8834 EVM GUI component installs.
14. After DRV8834 Installation, FTDI Installation begins. A screen as shown in Figure 14 appears, click
Extract to proceed.

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Figure 14. FTDI Installation Initialization
15. A screen as shown in Figure 15 appears, click Next to proceed.
Figure 15. Driver Installation Wizard

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16. The License Agreement appears on screen as shown below.
17. Read through the License Agreement carefully and enable the “I Accept this Agreement” radio button
and Click on Next.
Figure 16. License Agreement for FTDI Driver
18. Click Finish to complete the Driver Installation.

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Figure 17. Driver Installation Completion
19. Figure 18 appears denoting the completion of DRV8834 EVM GUI Installation. Click Finish.
Figure 18. Installation Complete
20. A Readme window as shown in Figure 19 appears displaying the link for LV 2014 RTE.

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Figure 19. Readme Window
WARNING
The DRV8834 EVM GUI requires the LabVIEW Run-Time Engine
2014 to be installed before the GUI executes. Please note the
application is not compatible with other versions of LabVIEW
Runtime Engine.
You can download National Instruments LabVIEW Run-Time Engine 2014
from the below link:
LabVIEW Run-Time Engine 2014
NOTE: DRV8834 EVM GGUI executable has been built in LabVIEW 2014 (32-bit) version, and it
expects the LabVIEW Run-Time Engine version to be LabVIEW Run-Time Engine (32-bit
version).
4 The Windows Application
The DRV8834EVM Windows application is the software counterpart for the DRV8834 EVM. It allows the
PC computer to connect to the MSP430F2617 microcontroller though an USB interface chip. Once
connection is established and commands are sent, microcontroller takes care of configuring control
signals and administering certain levels of automation, such as microstepping coordination, stepping rate
acceleration and deceleration, ITrip configuration and PWM generation.
The graphical user interface (GUI) has been designed to allow for all of the DRV8834 device’s
functionality to be tested without having to intervene with the hardware, except for the adjusting of the
reference voltage and decay selector switches.

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Figure 20. DRV8834EVM.exe Main Screen
All the control signals needed to control motor enablement (nENABLE or ENABLEx), direction of rotation
(PHASEx or DIR), current control (VREFx) and PWM control for both enablement and direction control
signals are made available throughout one of the three control tabs.
Each one of the three tabs will place the microcontroller and driver chip into one of the three operation
modes. The three tabs are described below.
4.1 Dual H Bridge Mode
See Figure 20.
While in this mode, the microcontroller treats the DRV8834 as a dual H-bridge driver with independent
current regulation, motor enablement and phase control.
In this mode, the Windows application offers control to ENABLE each of the two motors and control the
rotation direction. It also allows control of the speed and/or direction by offering access to a PWM
resource to each of the ENABLEx and PHASEx signals. Both H-bridges can be programmed with a
current regulation parameter by moving the VREFx slider. Other control signals are offered in the form of
check boxes.

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4.1.1 Internal Microstepper Control
Figure 21. Internal Microstepper Control
While in this mode, the microcontroller treats the DRV8834 as an internal indexer microstepper with up to
32 degrees of microstepping driver.
In this mode, the Windows application offers control to ENABLE the driver, change motor rotation, select
current regulation decay, select degrees of microstepping resolution and modify maximum current
programming.
The Windows application also offers access to a series of sophisticated algorithms which allow the
stepper motor actuation in both continuous rotation as well as position control mode. The algorithms offer
accurate acceleration and deceleration profiles which help in the obtaining of better motion quality and
performance.

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4.1.2 External Microstepper Control
Figure 22. External Microstepper Control
While in this mode, the microcontroller treats the DRV8834 as a dual H-bridge driver with independent
current regulation, motor enablement and phase control. Different than the dual H-bridge control mode in
which two DC motors can be driving, while in this operation style, the microcontroller will recognize
commands to issue high resolution microstepping commutation into a bipolar stepper motor.
In this mode, the Windows application offers control to change motor rotation and select degrees of
microstepping resolution. The decay is programmed into the microcontroller high resolution microstepping
algorithm to follow sine wave shape generation (slow decay while on quadrants 1 and 3, and mixed decay
while on quadrants 2 and 4). Current is set to 1.5-A sine wave peak. To change the maximum current, the
firmware’s internal look up table must be modified.
The Windows application also offers access to the same series of sophisticated algorithms which allow the
stepper motor actuation in both continuous rotation as well as position control mode. The algorithms offer
accurate acceleration and deceleration profiles which help in the obtaining of better motion quality and
performance.
4.2 The CONFIG Control Signal
In this Windows application, the CONFIG control signal is not made available to the user. The application
will modify the control signal according to which TAB is selected. When the communications are made and
any tab gains focus, a serial command is sent to the microcontroller to set the CONFIG control signal
accordingly. If the COM Port is not open, the serial command pertaining to this configuration is not sent.
4.3 Configuring Switches
Although the proper setting of the CONFIG control signal is made automatically, the EVM switches must
still be properly configured if correct operation is to be observed. Failure to properly set these switches will
result in problems with the current regulation and stepper motor functioning.

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The following table shows the recommended switch positions as a different tab is selected. "Required"
implies that the wrong operation will be observed if not followed. Optional implies that any other source
(like the pot or an external signal) can be used, although control through the Windows application will be
lost.
Table 2. Recommended Switch Positions
DUAL H-BRIDGE INTERNAL INDEXER EXTERNAL INDEXER
BDECAY MSP430 (optional) MSP430 (optional) MSP430 (required)
ADECAY MSP430 (optional) MSP430 (optional) MSP430 (required)
BVREF MSP430 (optional) AVREF (required) MSP430 (required)
AVREF MSP430 (optional) MSP430 (optional) MSP430 (required)
4.4 Menu Options
• .
Figure 23. File Menu
• Debug - The Debug option can be used for the following operations.
Figure 24. Debug Menu
•– Demo - By selecting the Demo in the submenu, the GUI runs in simulation mode, and by
unselecting it, the GUI runs in connected mode.
– Log to File - The log to file submenu is used to log the GUI activities to a log file that is specified.
– Debug log - The Debug log option enables to log all the activities of the user. If that is not selected,
only the high-level operations log.
• Help
– Clicking the About in the Help Menu
Figure 25. Help Menu
– The About Page provides the details like the Name of the GUI, GUI version, Supported OS and
Copyright Information.

I =
TRIP
xVREF
¾
5·RSENSE
, with R =
SENSE 0.2 W
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Figure 26. About Page
4.5 DRV8834 GPIO Control Signals
Once the application is communicating with the interface board, the control signals can be actuated by
checking or un-checking boxes on any of the respective control signals frames.
Functionality of control signals is as follows. A checked box translates to a HI level on the respective
control signal. Un-checked boxes translate to a LO level on the respective control signals.
4.6 Updating DAC Output for Current Control (VREF)
During evaluation, the user may want to study the operation of the ITRIP regulation scheme. Both
MSP430F2617 MCU DAC channels can be controlled through the provided sliders. Moving these sliders
will result on the regulated current to be directly proportional to the slider position per Equation 1.
(1)
It must be noted, however, that during stepper actuation with the external indexer method, the DAC
channels are controlled by the microcontroller’s microstepping application.
Figure 27. Current Control (VREF)
The 12-bit DAC channels 0/1 are connected to the DRV8834 VREF analog inputs VREF. Changing the
DAC digital value from 0 to 4095, changes the analog voltage at the respective VREF pin from 0 V to 2.5
V respectively. See Equation 2.