30 min

Power your devices with finesse using L6986H and TM4C1299KCZAD

Synchronous step-down marvel!

Step Down 2 Click with Fusion for Tiva v8

Published Aug 01, 2023

Click board™

Step Down 2 Click

Dev Board

Fusion for Tiva v8


NECTO Studio



This step-down converter proves invaluable in high-efficiency applications, as it minimizes energy dissipation and maximizes device runtime



Hardware Overview

How does it work?

Step Down 2 Click is based on  L6986HTR, a step-down monolithic switching regulator that delivers up to 2 A DC from STMicroelectronics. The output voltage adjustability ranges from 0.85 V to VIN. The "low consumption mode" (LCM) is designed for applications active during idle mode, so it maximizes the efficiency at light-load with controlled output voltage ripple. The "low noise mode" (LNM) makes the switching frequency constant and minimizes the output voltage ripple overload current range, meeting the low noise application specifications. The output voltage supervisor manages the reset phase for any digital load (µC, FPGA). The RST open collector output can also run voltage sequencing during the power-up phase. The synchronous rectification, designed for high efficiency at medium - heavy load, and the high switching frequency capability make the size of the application compact. Pulse-by-pulse current sensing on both power elements

implements effective constant current protection. The L6986H device is based on a "peak current mode" and constant frequency control. Consequently, the intersection between the error amplifier output and the sensed inductor current generates the PWM control signal to drive the power switch. The device features LNM (low noise mode), which implements a forced PWM operation over different loading conditions. The LNM features a constant switching frequency to minimize the noise in the final application and a constant voltage ripple at fixed VIN. The regulator in steady loading conditions never skips pulses, and it operates in continuous conduction mode (CCM) over the different loading conditions, thus making this operation mode ideal for noise-sensitive applications. The overvoltage protection monitors the VOUT pin and enables the low-side MOSFET to discharge the output capacitor if the output voltage is 20% over the nominal value.

This is second-level protection and should never be triggered in normal operating conditions if the system is properly dimensioned. In other words, the selection of the external power components and the dynamic performance determined by the compensation network should guarantee an output voltage regulation within the overvoltage threshold, even during the worst-case scenario regarding load transitions. The protection is reliable and can operate even during normal load transitions for a system whose dynamic performance is not in line with the load dynamic request. As a consequence, the output voltage regulation would be affected. Because of its features' main possibilities, the Step Down 2 Click is ideally used for programmable logic controllers (PLCs), decentralized intelligent nodes, sensors, and low noise applications (LNM).

Step Down 2 Click hardware overview image

Features overview

Development board

Fusion for TIVA v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from Texas Instruments, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over a WiFi network. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for TIVA v8 provides a fluid and immersive working experience, allowing access

anywhere and under any circumstances at any time. Each part of the Fusion for TIVA v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for TIVA v8 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.

Fusion for Tiva v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor

Texas Instruments

Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Power Supply

Take a closer look


Step Down 2 Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for Tiva v8 as your development board.

Fusion for PIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for Step Down 2 Click driver.

Key functions:

  • stepdown2_digital_read_rst - This function reads the digital signal from the RST pin

  • stepdown2_digital_write_cs - This function writes the specified digital signal to the CS pin

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

 * \file 
 * \brief Step Down 2 Click example
 * # Description
 * This example showcases how to initialize and use the Step Down 2 click. The click is a 
 * step-down monolithic switching regulator able to deliver up to 2 A (DC).
 * The demo application is composed of two sections :
 * ## Application Init 
 * This function initializes and configures the logger and click modules.
 * ## Application Task  
 * This function checks error input on the RST pin and reports if the device is working properly
 * or not. It does so every second.
 * \author MikroE Team
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "stepdown2.h"

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

static stepdown2_t stepdown2;
static log_t logger;

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

void application_init ( )
    log_cfg_t log_cfg;
    stepdown2_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.

    stepdown2_cfg_setup( &cfg );
    stepdown2_init( &stepdown2, &cfg );

    stepdown2_digital_write_cs( &stepdown2, 1 );
    Delay_100ms( );

void application_task ( )
    if ( stepdown2_digital_read_rst( &stepdown2 ) )
        log_printf( &logger, " * The device works as it should. *\r\n" );
        log_printf( &logger, " * The device does not work as it should. *\r\n" );

    Delay_1sec( );

void main ( )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support