Datasheet

www.ti.com

Windows Application

After opening the application, the order of events should be:

1. Select the COM port from the COMx drop-down box.

2. Press Connect. If COM ports are available, the application searches for the EVM. If no EVM is found,

an error message notifies the user. If the port is available and communications are successfully made,

the menu item changes its Connect caption to Disconnect. Pressing Disconnect to disables the serial

communications.

3. After pressing any command button, <1><0><0> should return on the bottom status bar as an

acknowledgment of proper communications taking place with the board.

4. The application is now ready for use.

5. Closing down the application (through the Close X or through File → Exit) closes the serial port

connection, it is not necessary to press Disconnect before closing down the application.

4.2 DRV8844 GPIO Control Signals

Once the application is communicating with the interface board, the control signals can be actuated by

clicking on the respective pin. A signal with a logic LO state is represented with the color red, whereas the

same signal is represented with the color green once its state is switched to logic HI.

4.3 PWM Control

The four INx signals are actuated through a series of PWM outputs generated by the onboard MSP430

microcontroller. The PWM duty cycle is programmed by either moving the respective slider or changing

the duty cycle percentage on the number box, see Figure 4.

When engaging the PWM sliders, the output enters PWM mode. The respective ENx pin turns from either

green or red, to orange, depicting a PWM-based output. Pressing the orange pin button again takes the

same output to 100% duty cycle, while the orange pin changes to a green color. Whenever the PWM

sliders are moved to the 0% or 100% position, the respective pin changes to a red or green color

respectively. That is, for each ENx pin, red stands for 0% duty cycle (or channel off), whereas green

stands for 100% duty cycle (or channel full on).

Figure 4. DRV8844 PWM Control Window

SLVU762–August 2012 DRV8844 Evaluation Module

Submit Documentation Feedback