Intermediate
30 min
0

Unleash the power of lightning-fast AC/DC current measurements with LTS 6-NP and STM32F732IE

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LEM Click with Fusion for STM32 v8

Published Sep 30, 2023

Click board™

LEM Click

Development board

Fusion for STM32 v8

Compiler

NECTO Studio

MCU

STM32F732IE

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Hardware Overview

How does it work?

LEM Click is based on the LTS 6-NP, a current transducer from Lem. It acts as a transformer with 2000 turns as a secondary coil and a load resistance of 2kΩ and above. The primary coil is a wire of the load itself, threaded through the middle of the current transducer while fully isolated and galvanic separated from the secondary coil. The LTS 6-NP uses the Hall effect to output the values regarding the current that passes through. The sensor output passes to the MCP607, a micropower CMOS operational amplifier from Microchip. It is a unity-gain stable, low offset voltage OpAmp that includes rail-to-rail

output, swing capability, and low input bias current. The output values from the operational amplifier pass to the MCP3201, a 12-bit analog-to-digital converter with an SPI serial interface from Microchip. The MCP3201 provides a single pseudo-differential input features on-chip, sample and hold, a maximum sampling rate of up to 100ksps, and more. The MCP3201 gets the 2.048V reference voltage from the MAX6106, a low-cost, micropower, low-dropout, high-output-current voltage reference from Analog Devices. The LEM Click uses the 3-Wire SPI serial interface of the MCP3201 to communicate with the host MCU supporting SPI 0

and SPI 3 modes with a frequency of up to 1.6MHz. The voltage amplified through the MCP607 can be directly monitored through the AN pin of the mikroBUS™ socket, which is useful if the host MCU has a higher ADC resolution. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR 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.

LEM Click hardware overview image

Features overview

Development board

Fusion for STM32 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 STMicroelectronics, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. 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 STM32 v8 provides a fluid and immersive working experience, allowing

access anywhere and under any circumstances at any time. Each part of the Fusion for STM32 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 STM32 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 STM32 v8 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

ARM Cortex-M7

MCU Memory (KB)

512

Silicon Vendor

STMicroelectronics

Pin count

176

RAM (Bytes)

262144

Used MCU Pins

mikroBUS™ mapper

Analog Output
PF3
AN
NC
NC
RST
SPI Chip Select
PC3
CS
SPI Clock
PI1
SCK
SPI Data OUT
PI2
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

LEM 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 STM32 v8 as your development board.

Fusion for PIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
v8 SiBRAIN 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 LEM Click driver.

Key functions:

  • lem_get_current - Function is used to read current in amperes or milliamperes

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 Lem Click example
 * 
 * # Description
 * Demo app measures and displays current by using LEM click board.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initalizes SPI, LOG and click drivers.
 * 
 * ## Application Task  
 * This is an example that shows the capabilities of the LEM click by measuring 
 * current passing through the conductor placed through the hole on the sensor.
 * 
 * \author Jovan Stajkovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "lem.h"

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

static lem_t lem;
static log_t logger;
static float current;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    lem_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.

    lem_cfg_setup( &cfg );
    LEM_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    lem_init( &lem, &cfg );
    log_printf( &logger, "---------------------\r\n" );
    log_printf( &logger, "      LEM Click      \r\n" );
    log_printf( &logger, "---------------------\r\n" );
}

void application_task ( void )
{
    current = lem_get_current( &lem, LEM_MILIAMP_COEF );
    
    log_printf( &logger, " Current : %.2f mA \r\n", current );
    log_printf( &logger, "---------------------\r\n" );
    Delay_ms( 1000 );
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources