3.5.2Step by Step control

Schematic

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Pressing the Start Steps button, will start the timer and pulses will be generated at the rate specified by the decimal number at the PPS text box. Once the Start Steps button is pressed it becomes the Stepping button. Press the Stepping button to stop the stepper motion.

When the motor is stepping, the Update Speed button becomes enabled. Speed can be updated by modifying the PPS text box and then pressing the Update Speed button. The Update Speed button is disabled every time the motor is not turning because the stepping has been halted by pressing the Stepping button.

3.5.2Step by Step control

The Step Control frame has a series of tools to control the stepping of the motor on a predetermined number of steps fashion.

The Pulse Step button allows for a single step to be issued. At the same time, the STEP Control check box allows the control of the STEP signal in the same fashion that other GPIO signals on the Signals frame could be set and cleared. Checked stands for HI and unchecked for LO. Remember that a STEP takes place when STEP goes from LO to HI.

Figure 10. Step Control Frame

To move the motor a number of steps and then stop, fill the # of Steps text box with a decimal number from 0 to 65535 and the motor will move that number of steps at the speed specified on the PPS text box. No acceleration or deceleration takes place under this function.

4Schematic

The schematic can be found on the provided CD under the EVM Related folder.

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Laser and Motor Drives

SLVA344A–July 2009–Revised September 2009

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Texas Instruments DRV8811EVM manual Schematic, Step by Step control, Step Control Frame