Texas Instruments DRV8811EVM 用户手册
3.3
Updating DAC Output for Current Control (VREF/DECAY)
VREF = DAC_VALUE
·
2.5
V
¾
4095
(1)
3.4
Updating DAC Output for Decay Control (DECAY)
DECAY = DAC_VALUE
·
2.5
V
¾
4095
(2)
3.5
Operating the Stepper Motor
3.5.1
Turning the Stepper Motor
Windows Application
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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.
translates to a LO level on the respective control signal.
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.
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 6. 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
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
.
Where VREF is the output voltage and DAC_VALUE is a number from 0 to 4095.
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.
microcontroller interface (JP6 is set to INT), then the slider bar on the Current Control frame can be used
to set the DECAY voltage.
Figure 7. Current Control Frame
The MSP430F1612 12 bit DAC channel 1 is connected to the DRV8811 DECAY analog input. Changing
the DAC digital value from 0 to 4095, changes the analog voltage at the DECAY pin from 0 V to 2.5 V
respectively. See
the DAC digital value from 0 to 4095, changes the analog voltage at the DECAY pin from 0 V to 2.5 V
respectively. See
.
Where DECAY is the output voltage and DAC_VALUE is a number from 0 to 4095.
The Windows Application, in conjunction with the MSP430F1612 microcontroller, utilizes a series of timers
to coordinate the rate of steps sent to the device. Once all the control signals are configured accordingly
(ENABLEn = LO, SLEEPn = HI, RESETn = HI; DIR, USM0 and USM1 can be HI or LO depending on
preferred mode of operation; SRn must be L, if external diodes are not populated), the motor is ready to
be turned.
to coordinate the rate of steps sent to the device. Once all the control signals are configured accordingly
(ENABLEn = LO, SLEEPn = HI, RESETn = HI; DIR, USM0 and USM1 can be HI or LO depending on
preferred mode of operation; SRn must be L, if external diodes are not populated), the motor is ready to
be turned.
10
Laser and Motor Drives
SLVA344A – July 2009 – Revised September 2009