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

2.1.6.1 DRV8421A: Brushed-DC Motor Control

The MSP430 produces PWM signals for the IN1, IN2, IN3 and IN4 pins with duty cycles proportional to the voltage from the MCU Ctrl 1 and MCU Ctrl 2 potentiometers. To achieve a 1 or 0 for the outputs, the input potentiometers must be turned completely clockwise or counterclockwise. The table below shows how to configure the potentiometers for different modes of operation.

Table 2-2 DRV8421A Control
IN1/IN3 IN2/IN4 OUT1 OUT2 OUT3 OUT4 FUNCTION

Low – turn MCU CTRL 1 completely counter-clockwise

Low – turn MCU CTRL 2 completely counter-clockwise

Hi-Z

Hi-Z

Hi-Z

Hi-Z

Standby Mode (Hi-Z)

High – turn MCU CTRL 1 completely clockwise

Low – turn MCU CTRL 2 completely counter-clockwise

1

0

1

0

Forward

Low – turn MCU CTRL 1 completely counter-clockwise

High – turn MCU CTRL 2 completely clockwise

0

1

0

1

Reverse

High – turn MCU CTRL 1 completely clockwise

High – turn MCU CTRL 2 completely clockwise

0

0

0

0

Brake
Note:

Due to the limitation of two inputs, the EVM firmware in place is only configured to control two outputs. Separate firmware must be configured on an external MCU with inputs connected to J7 to utilize all four outputs with independent half-bridge control.

DRV8421AEVM, DRV8421BEVM EVM Controls for Brushed-DC Motor Operation with DRV8421A Figure 2-6 EVM Controls for Brushed-DC Motor Operation with DRV8421A