Beginner
10 min

Step confidently into the future of power management with MAX17624 and ATmega328P

Transform power with precision using our step-down DC-DC wizardry

Step Down 7 Click with Arduino UNO Rev3

Published Feb 14, 2024

Click board™

Step Down 7 Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Our synchronous step-down DC-DC converter stands as a pinnacle of power efficiency, offering precise voltage regulation and current control to meet the demands of your electronic applications.

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Hardware Overview

How does it work?

Step Down 7 Click is based on the MAX17624, a synchronous step-down converter with integrated MOSFETs from Analog Devices. The converter uses soft start ramp technology, allowing a smooth output voltage increase. The output voltage is monitored through a resistor divider as feedback. On this Click board™, the resistor divider consists of a resistor and the MCP4661T, an 8-bit dual digital POT with volatile memory from Microchip. This 50K digital potentiometer has a resistor ladder with ends connected to the analog switches and terminals A and B. The 256 resistors give 257 wiper positions. The potentiometer features high-speed read/write to the wiper and increment/decrement of wiper serial protocols. The MAX17624 has two selectable modes of operation, the PWM and the PFM modes. The PWM mode is used in fixed-frequency operations

with a fixed 4MHz switching frequency. This mode allows the device’s output current to go negative and is useful in frequency-sensitive applications as it provides fixed switching frequency operations at all loads. The PWM mode gives lower efficiency at light loads compared to a PFM mode of operation. The PFM mode disables the negative output current from the device, and skips pulse at light loads for better efficiency. Another feature of the step-down converter is Power Good, which indicates the output voltage status. Step Down 7 Click uses I/O pins to communicate with the host MCU. To change to the desired mode, you can set a logic state of the MD pin LOW for the PWM mode of operation; otherwise, the PFM mode is selected. Power Good output can be monitored over the PG pin. With the enabled EN pin, the MAX17624 will first go into soft start mode and,

after 1ms, will smoothly increase the voltage. The feedback is provided over the resistor divider and the digital potentiometer, which uses a standard 2-Wire I2C interface to communicate with the host MCU, supporting frequencies of 100KHz, 400KHz, and 3.4MHz. The I2C address can be selected over the combination of the three jumpers, with all of them set to 0 by default. 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. Also, this 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.

Step Down 7 Click hardware overview image

Features overview

Development board

Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an

ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the

first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.

Arduino UNO Rev3 double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

AVR

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

You complete me!

Accessories

Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Arduino UNO accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Enable
PD2
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Mode Selection
PD6
PWM
Power Good Indicator
PC3
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PC5
SCL
I2C Data
PC4
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Step Down 7 Click Schematic schematic

Step by step

Project assembly

Click Shield for Arduino UNO front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.

Click Shield for Arduino UNO front image hardware assembly
Arduino UNO Rev3 front image hardware assembly
Charger 27 Click front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Board mapper by product8 hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Arduino UNO MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image 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 Step Down 7 Click driver.

Key functions:

  • stepdown7_set_mode - Step Down 7 mode selection function.

  • stepdown7_get_pg_state - Step Down 7 get PG pin state function.

  • stepdown7_set_output - Step Down 7 set output voltage.

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 main.c
 * @brief Step Down 7 Click example
 *
 * # Description
 * This library contains API for the Step Down 7 Click driver.
 * This driver provides the functions to set the output voltage treshold.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization of I2C module and log UART.
 * After driver initialization, default settings sets output voltage to 1.5 V.
 *
 * ## Application Task
 * This example demonstrates the use of the Step Down 7 Click board™ by changing 
 * output voltage every 5 seconds starting from 1.5 V up to 3.3 V.
 * 
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "stepdown7.h"

static stepdown7_t stepdown7;
static log_t logger;

/**
 * @brief Output level printing function.
 * @details This function is used to log value of the selected voltage to UART terminal.
 * @param[in] sel_level : Selected voltage level.
 * @return Nothing.
 * @note None.
 */
static void print_selected_output_level ( uint8_t sel_level );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    stepdown7_cfg_t stepdown7_cfg;  /**< Click config object. */

    /** 
     * 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.
    stepdown7_cfg_setup( &stepdown7_cfg );
    STEPDOWN7_MAP_MIKROBUS( stepdown7_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == stepdown7_init( &stepdown7, &stepdown7_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( STEPDOWN7_ERROR == stepdown7_default_cfg ( &stepdown7 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    for ( uint8_t n_cnt = STEPDOWN7_OUTPUT_1V5; n_cnt <= STEPDOWN7_OUTPUT_3V3; n_cnt++ )
    {
        stepdown7_set_output( &stepdown7, n_cnt );
        log_printf( &logger, " Selected output is:" );
        print_selected_output_level ( n_cnt );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        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;
}

static void print_selected_output_level ( uint8_t sel_level )
{
    switch ( sel_level )
    {
        case ( STEPDOWN7_OUTPUT_1V5 ):
        {
            log_printf( &logger, " 1.5V\r\n" );
            break;
        }
        case ( STEPDOWN7_OUTPUT_2V5 ):
        {
            log_printf( &logger, " 2.5V\r\n" );
            break;
        }
        case ( STEPDOWN7_OUTPUT_3V3 ):
        {
            log_printf( &logger, " 3.3V\r\n" );
            break;
        }
        default:
        {
            log_printf( &logger, " ERROR\r\n" );
        }
    }
}

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

Additional Support

Resources

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