Achieve exceptional results with DRV887N and ATmega644

Mastering the art of brushed motor control

Published May 31, 2023

Click board™

H-Bridge 7 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega644

Experience the seamless integration of brushed motor control and save your battery life by using this solution that supports a wide range of output load currents for various motors and loads

Hardware Overview

How does it work?

H-Bridge 7 Click is based on the DRV8876N, N-channel H-bridge motor driver from Texas Instruments that operates from a supply voltage of 4.5V to 37V, supporting a wide range of output load currents for various types of motors and loads. This device integrates an H-bridge output power stage that can be operated in control modes set by the PMODE pin setting. The device also integrates a charge pump regulator to support more efficient high-side N-channel MOSFETs and 100% duty cycle operation. The device operates from a single power supply input (VM) which can be directly connected to a battery or DC voltage supply. The nSLEEP pin (nSL pin on the mikroBUS™) provides an ultra-low power mode to minimize current draw during system inactivity.

Also, this device is fully protected against supply undervoltage, charge pump undervoltage, output overcurrent, and device overtemperature events. H-Bridge 7 Click supports different control schemes with the EN/IN1 and PH/IN2 pins. The control mode is selected through the PMODE pin with either logic low, logic high, or setting the pin Hi-Z (in this case, PMODE is on the logic low level, which means that the device is latched into PH/EN mode). PH/EN mode allows for the H-bridge to be controlled with a speed and direction type of interface. In this configuration, Click board™ drives a bidirectional current through an external load (such as a brushed DC motor), and the H-bridge polarity and duty cycle are controlled with a PWM and IO resource from the external controller

to the EN/IN1 and PH/IN2 pins. The device is then configured for the PH/EN control mode by tying the PMODE pin to GND. Some applications of DRV8876N include brushed DC motors, solenoids, and actuators, but they also can be utilized to drive many common passive loads such as LEDs, resistive elements, relays, and more. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

H-Bridge 7 Click hardware overview image

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

4096

You complete me!

Accessories

DC Gear Motor - 430RPM (3-6V) represents an all-in-one combination of a motor and gearbox, where the addition of gear leads to a reduction of motor speed while increasing the torque output. This gear motor has a spur gearbox, making it a highly reliable solution for applications with lower torque and speed requirements. The most critical parameters for gear motors are speed, torque, and efficiency, which are, in this case, 520RPM with no load and 430RPM at maximum efficiency, alongside a current of 60mA and a torque of 50g.cm. Rated for a 3-6V operational voltage range and clockwise/counterclockwise rotation direction, this motor represents an excellent solution for many functions initially performed by brushed DC motors in robotics, medical equipment, electric door locks, and much more.

Used MCU Pins

mikroBUS™ mapper

H-Bridge Control 1

PA6

RST

Sleep Mode

PA5

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

H-Bridge Control 2

PD4

PWM

Fault Indicator

PD2

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

EasyAVR v7 Access DIP MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection Necto Step hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for H-Bridge 7 Click driver.

Key functions:

void hbridge7_motor_state ( uint8_t state ) Set motor state
void hbridge7_motor_control ( uint8_t ctrl ) Set motor control
uint8_t hbridge7_get_fault_state ( void ) Get Fault pin state

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * \file 
 * \brief H-BRIDGE 7 Click example
 * 
 * # Description
 * This example demonstrates the use of H-Bridge 7 Click board. 
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes the driver and makes an initial log.
 * 
 * ## Application Task  
 * Drives the motor in the forward direction for 5 seconds, then pulls brake for 2 seconds, 
 * and after that drives it in the reverse direction for 5 seconds, and finally, 
 * disconnects the motor for 2 seconds. Each step will be logged on the USB UART where
 * you can track the program flow.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "hbridge7.h"

// ------------------------------------------------------------------ VARIABLES

static hbridge7_t hbridge7;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    hbridge7_cfg_t cfg;

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info(&logger, "---- Application Init ----");

    //  Click initialization.

    hbridge7_cfg_setup( &cfg );
    HBRIDGE7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    hbridge7_init( &hbridge7, &cfg );
}

void application_task ( void )
{
    log_printf( &logger, "The motor turns forward! \r\n" );
    hbridge7_motor_control( &hbridge7, HBRIDGE7_MOTOR_FORWARD );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    log_printf( &logger, "Pull brake! \r\n" );
    hbridge7_motor_control( &hbridge7, HBRIDGE7_MOTOR_BRAKE );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    log_printf( &logger, "The motor turns in reverse! \r\n" );
    hbridge7_motor_control( &hbridge7, HBRIDGE7_MOTOR_REVERSE );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    log_printf( &logger, "The motor is disconnected (High-Z)!  \r\n" );
    hbridge7_motor_control( &hbridge7, HBRIDGE7_MOTOR_SLEEP );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

// ------------------------------------------------------------------------ END