ECG at your fingertips with ADS1194 and STM32L496AG

Unveiling vital rhythms

ECG 2 Click with Discovery kit with STM32L496AG MCU

Published Jul 22, 2025

Click board™

ECG 2 Click

Dev. board

Discovery kit with STM32L496AG MCU

Compiler

NECTO Studio

MCU

STM32L496AG

Experience the power of real-time ECG monitoring that provides instant and accurate insights into heart health

Hardware Overview

How does it work?

ECG 2 Click is based on the ADS1194, a low-power, 8-channel, 16-bit analog front-end for biopotential measurements from Texas Instruments. The ADS1194 is a multichannel simultaneous sampling delta-sigma analog-to-digital converter with a built-in programmable gain amplifier, internal reference, and onboard oscillator. It has a flexible input multiplexer per channel that can be independently connected to the internally generated signals for test, temperature, and lead-off detection. This ADC can sample data in a range of 125sps up to 8ksps data rates, with a programmable gain in 1, 2, 3, 4, 6, 8, or 12 steps. In addition, the ECG 2 Click features the built-in right leg drive amplifier, lead-off detection, WCT, test signals, pace detection channel selection, and more. The ECG 2 Click can work in several modes. The Continuous mode is ideal for applications that require a fixed stream of conversion results. The Single-Shot conversion mode is provided for applications that require a non-standard or non-continuous data rate. An onboard 3.5mm phone

jack is used to connect cables/electrodes to the Click board™. The electrode collects voltage from the skin, after which the signal is amplified, filtered, and sent to the host MCU over the mikroBUS™ socket. The three electrodes should be placed on the left arm, right arm, and the left side of the abdomen (below the heart), on the left leg. In addition to the phone jack, the ECG 2 Click includes screw terminals for a 4-wire measurement. ECG 2 click can also be connected by four electrodes placed on both arms and legs. The final measurement results can be displayed as an Electrocardiogram using a free app, the MikroPlot, a free data visualization tool (Windows). It's a simple tool to help you visualize sensor data recorded over time, suitable for biosignals (ECG, EEG, EMG) and environmental data logging (temperature, humidity, and more). The graph is generated from data sent from the MCU (ADC values from ECG 2 click input + timestamp). The app can receive data sets from a microcontroller through a USB UART connection. ECG 2 Click uses

a standard 4-Wire SPI serial interface to communicate with the host MCU. The data-ready output is used as a status signal to indicate when data are ready, where the DRD pin will go LOW if new data are available. In addition, other pins meet the ECG 2 Click's functionalities. The ADS1194 can be reset over the RST pin with an active LOW logic state, while it can be powered down with an active LOW on the PWD pin. The host MCU can be used to detect the presence of the pulse by bringing out the output of the PGA at the PAC pin (TEST PACE OUT1). This Click board™ can be operated only with a 3.3V logic voltage level while it uses a 5V for analog power supply via LDO (3V stabilized). The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Features overview

Development board

The 32L496GDISCOVERY Discovery kit serves as a comprehensive demonstration and development platform for the STM32L496AG microcontroller, featuring an Arm® Cortex®-M4 core. Designed for applications that demand a balance of high performance, advanced graphics, and ultra-low power consumption, this kit enables seamless prototyping for a wide range of embedded solutions. With its innovative energy-efficient

architecture, the STM32L496AG integrates extended RAM and the Chrom-ART Accelerator, enhancing graphics performance while maintaining low power consumption. This makes the kit particularly well-suited for applications involving audio processing, graphical user interfaces, and real-time data acquisition, where energy efficiency is a key requirement. For ease of development, the board includes an onboard ST-LINK/V2-1

debugger/programmer, providing a seamless out-of-the-box experience for loading, debugging, and testing applications without requiring additional hardware. The combination of low power features, enhanced memory capabilities, and built-in debugging tools makes the 32L496GDISCOVERY kit an ideal choice for prototyping advanced embedded systems with state-of-the-art energy efficiency.

Discovery kit with STM32L496AG MCU double side image

Microcontroller Overview

MCU Card / MCU

Architecture

ARM Cortex-M4

MCU Memory (KB)

1024

Silicon Vendor

STMicroelectronics

Pin count

169

RAM (Bytes)

327680

You complete me!

Accessories

3-wire ECG/EMG cable comes with a convenient 3.5mm phone jack, and it is designed for electrocardiogram recording. This 1m cable is a practical companion for medical professionals and enthusiasts. To complement this cable, you can also use single-use adhesive ECG/EMG electrodes measuring 48x34mm, each equipped with an ECG/EMG cable stud adapter. These electrodes ensure a seamless experience when paired with our ECG/EMG cable and guarantee reliable ECG/EMG signal transmission for comprehensive cardiac monitoring. Trust in the accuracy and convenience of this setup to effortlessly record electrocardiograms and electromyograms with confidence.

Used MCU Pins

mikroBUS™ mapper

Test Pace Out

PA4

Reset

PB2

RST

SPI Chip Select

PG11

SPI Clock

PI1

SCK

SPI Data OUT

PD3

MISO

SPI Data IN

PI3

MOSI

Power Supply

3.3V

Ground

GND

Power Down

PA0

PWM

Data Ready

PH2

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Discovery kit with STM32H750XB MCU front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Discovery kit with STM32L496AG MCU as your development board.

Thermo 21 Click front image hardware assembly

Thermo 21 Click complete accessories setup image hardware assembly

Board mapper by product7 hardware assembly

Discovery kit with STM32H750XB MCU NECTO MCU Selection Step hardware assembly

Necto No Display image step 8 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 ECG 2 Click driver.

Key functions:

ecg2_read_an_pin_value - ECG 2 read AN pin value function
ecg2_send_command - ECG 2 send command function
ecg2_read_channel_data - ECG 2 read data channel function

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 ECG2 Click example
 *
 * # Description
 * This is an example that demonstrates the use of the ECG 2 Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes SPI and UART communication, configures INT pin as INPUT, RST pin as OUTPUT, CS pin as 
 * OUTPUT and PWM pin as OUTPUT. Initializes SPI driver, initializes ECG2 Click, sends START and 
 * RDATAC opcodes.
 *
 * ## Application Task
 * Captures readings from channel and plots data to serial plotter.
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "ecg2.h"

static ecg2_t ecg2;
static log_t logger;
uint32_t time;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ecg2_cfg_t ecg2_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.
    ecg2_cfg_setup( &ecg2_cfg );
    ECG2_MAP_MIKROBUS( ecg2_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == ecg2_init( &ecg2, &ecg2_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    SET_SPI_DATA_SAMPLE_EDGE;
    
    if ( ECG2_ERROR == ecg2_default_cfg ( &ecg2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    Delay_ms ( 100 );
    ecg2_send_command( &ecg2, ECG2_START_CONVERSION );
    Delay_ms ( 100 );
    ecg2_send_command( &ecg2, ECG2_ENABLE_READ_DATA_CONT_MODE );
    Delay_ms ( 100 );
    
    log_info( &logger, " Application Task " );
    Delay_ms ( 100 );
}

void application_task ( void ) 
{   
    uint16_t ecg_an = 0;
    ecg2_read_channel_data( &ecg2, 5, &ecg_an );
    log_printf( &logger, " %.6u, %.8lu \r\n", ecg_an, time );
    time += 5;
    Delay_ms ( 5 );   
}

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