Create a load-switching solution with L9026 and ATmega644

Save your energy when a load isn't needed

Published Mar 06, 2023

Click board™

SolidSwitch 2 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega644

Provide power across different loads with individual control of each one

Hardware Overview

How does it work?

SolidSwitch 2 Click is based on the L9026, an automotive multi-channel relay driver optimized for automotive relay and LED applications from STMicroelectronics. Eight channels of the L9026 represent two high-side and six configurable high-side/low-side drivers, which can be driven by an SPI interface or by two dedicated parallel inputs (IN0 and IN1 pins routed to the PWM and INT pins of the mikroBUS™ socket). Operating from an external power supply from 3V up to 18V, it provides a maximum current of 1A on its output terminals. This board is an excellent choice for automotive, resistive, and inductive applications (LEDs and relays) and capacitive loads.

As mentioned, this Click board™ communicates with MCU through a standard SPI interface to control and configure the loads and the device. The L9026 also offers advanced diagnostic and protection features such as short-to-ground, open load, overcurrent, and overtemperature detections, with status feedback of all diagnostic functions provided via the SPI interface. Besides, the L9026 also features Idle mode for reduced current consumption, controlled via IDL pin routed to the AN pin of the mikroBUS™ socket and the “Limp home” mode. This mode allows using two selected drivers in particularly faulty conditions, such as SPI fault, micro fault, or supply undervoltage.

The device can guarantee operations under a cranking scenario with a supply voltage down to 3V, ensuring a low quiescent current under reset conditions. 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.

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

Used MCU Pins

mikroBUS™ mapper

Idle Mode

PA7

RST

SPI Chip Select

PA5

SPI Clock

PB7

SCK

SPI Data OUT

PB6

MISO

SPI Data IN

PB5

MOSI

Power Supply

3.3V

Ground

GND

Parallel Command 0

PD4

PWM

Parallel Command 1

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 SolidSwitch 2 Click driver.

Key functions:

solidswitch2_write_register This function writes a desired data to the selected register by using SPI serial interface.
solidswitch2_toggle_in0_pin This function toggles the IN0 pin logic state.
solidswitch2_toggle_in1_pin This function toggles the IN1 pin logic 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 main.c
 * @brief SolidSwitch 2 Click example
 *
 * # Description
 * This example demonstrates the use of SolidSwitch 2 click board by controlling the output state.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which maps outputs as follows:
 * OUT2   - IN0,
 * OUT3   - IN1,
 * OUT4-5 - PWM GEN,
 * OUT6-7 - PWM LED.
 *
 * ## Application Task
 * Changes the PWM GEN (max to min) and PWM LED (min to max) duty cycle and toggles the IN0 and IN1
 * pins every 250ms. The duty cycle values and INx toggle messages will be displayed on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "solidswitch2.h"

static solidswitch2_t solidswitch2;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    solidswitch2_cfg_t solidswitch2_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.
    solidswitch2_cfg_setup( &solidswitch2_cfg );
    SOLIDSWITCH2_MAP_MIKROBUS( solidswitch2_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == solidswitch2_init( &solidswitch2, &solidswitch2_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( SOLIDSWITCH2_ERROR == solidswitch2_default_cfg ( &solidswitch2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    for ( uint16_t duty_cycle = SOLIDSWITCH2_MIN_DUTY_CYCLE; duty_cycle <= SOLIDSWITCH2_MAX_DUTY_CYCLE; duty_cycle += 5 )
    {
        if ( SOLIDSWITCH2_OK == solidswitch2_write_register ( &solidswitch2, SOLIDSWITCH2_REG_PWM_GEN_DC, 
                                                              ( uint8_t ) ( SOLIDSWITCH2_MAX_DUTY_CYCLE - duty_cycle ) ) )
        {
            log_printf ( &logger, " PWM GEN DC: %u\r\n", ( SOLIDSWITCH2_MAX_DUTY_CYCLE - duty_cycle ) );
        }
        if ( SOLIDSWITCH2_OK == solidswitch2_write_register ( &solidswitch2, SOLIDSWITCH2_REG_PWM_LED_DC, ( uint8_t ) duty_cycle ) )
        {
            log_printf ( &logger, " PWM LED DC: %u\r\n", duty_cycle );
        }
        solidswitch2_toggle_in0_pin ( &solidswitch2 );
        log_printf ( &logger, " Toggle IN0 pin\r\n" );
        solidswitch2_toggle_in1_pin ( &solidswitch2 );
        log_printf ( &logger, " Toggle IN1 pin\r\n\n" );
        Delay_ms ( 250 );
    }
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}

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