VREF = DAC_VALUE
·
2.5
V
¾
4095
Windows Application
19
SLVA344C – July 2009 – Revised July 2019
Copyright © 2009–2019, Texas Instruments Incorporated
Laser and Motor Drives
Figure 27. Signals Frame
A checked checkbox translates to a HI level on the respective control signal. A un-checked checkbox
translates to a LO level on the respective control signal.
3.3
Updating DAC Output for Current Control (VREF/DECAY)
If the DRV8811 EVM has been configured to accept VREF analog voltages through the MSP430
microcontroller interface (JP1 is set to INT), then the slider bar on the Current Control frame can be used
to set the VREF voltage.
Figure 28. Curent Control Frame
The MSP430F1612 12-bit DAC channel 0 is connected to the DRV8811 VREF analog input. Changing the
DAC digital value from 0 to 4095, changes the analog voltage at the VREF/DECAY pin from 0 V to 2.5 V
respectively. See
(1)
Where VREF is the output voltage and DAC_VALUE is a number from 0 to 4095.
3.4
Updating DAC Output for Decay Control (DECAY)
If the DRV8811 EVM has been configured to accept DECAY analog voltages through the MSP430
microcontroller interface (JP6 is set to INT), then the slider bar on the Current Control frame can be used
to set the DECAY voltage.
