SLOU571 June   2024

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 EVM Setup and Mode Select
      1. 2.1.1 Jumpers
      2. 2.1.2 DRV8421A: Brushed-DC Setup
      3. 2.1.3 DRV8421A: Stepper Setup
      4. 2.1.4 DRV8421B: Brushed-DC Setup
      5. 2.1.5 DRV8421B: Stepper Setup
      6. 2.1.6 EVM Control
        1. 2.1.6.1 DRV8421A: Brushed-DC Motor Control
        2. 2.1.6.2 DRV8421A: Stepper Motor Control
        3. 2.1.6.3 DRV8421B: Brushed-DC Motor Control
        4. 2.1.6.4 DRV8421B: Stepper Motor Control
      7. 2.1.7 Parallel Mode
        1. 2.1.7.1 DRV8421A: Parallel Mode
        2. 2.1.7.2 DRV8421B: Parallel Mode
      8. 2.1.8 Removing and Installing Supported Motor Drivers
  9. 3Hardware Design Files
    1. 3.1 Schematics
    2. 3.2 PCB (Top-Assembly View)
    3. 3.3 Bill of Materials (BOM)
  10. 4Additional Information
    1. 4.1 Trademarks

2.1.6.2 DRV8421A: Stepper Motor Control

The MSP430 produces PWM signals for the IN1, IN2, IN3 and IN4 pins with frequencies proportional to the voltage from the MCU Ctrl 1 potentiometer.

MCU Ctrl 1 controls the speed of the stepper motor. Begin with potentiometer fully clockwise and slowly rotate counter-clockwise to increase speed.

DRV8421AEVM, DRV8421BEVM Speed Control Direction Figure 2-7 Speed Control Direction

When operating in Stepper Mode (J2) and Step Select (J10), the speed of the stepper motor is controlled by MCU Ctrl 1 potentiometer.

DRV8421AEVM, DRV8421BEVM EVM Controls for Stepper Motor Operation with DRV8421A Figure 2-8 EVM Controls for Stepper Motor Operation with DRV8421A

The following figure shows an example of input and output waveforms while in full-step mode. The DRV8421B is configured in a full-step sequence by default.

DRV8421AEVM, DRV8421BEVM Full-Step Sequence Waveforms Figure 2-9 Full-Step Sequence Waveforms

The following figure shows an example of input and output waveforms while in half-step mode. This step sequence is only available through the Step Select jumper (J10) for the DRV8421A only.

DRV8421AEVM, DRV8421BEVM Half-Step Sequence Waveforms Figure 2-10 Half-Step Sequence Waveforms