30 min

Measure motion and acceleration with KX134-1211 and STM32F302VC

The dance of data: How accelerometers revolutionize our world

Accel 20 Click with Fusion for ARM v8

Published Oct 05, 2023

Click board™

Accel 20 Click

Development board

Fusion for ARM v8


NECTO Studio



This solution makes it possible to enhance safety by monitoring and alerting for sudden movements or impacts



Hardware Overview

How does it work?

Accel 20 Click is based on the KX134-1211, a highly reliable digital triaxial acceleration sensor with a feature set optimized for machine condition monitoring from Rohm Semiconductor. The KX134-1211 is highly configurable with a programmable acceleration range of ±8/±16/±32/±64g, providing signal conditioning and intelligent user-programmable application algorithms with improved linearity over the entire temperature range. It also has an Advanced Data Path (ADP) technology, which allows noise filtering and sensor signal processing, usually carried out by the MCU, to be performed by the accelerometer. They contribute to reducing MCU load and power consumption and improving application performance. Acceleration sensing is based on the principle of a differential capacitance arising from the acceleration-induced motion of

the sensing element, which is hermetically sealed at the wafer level by bonding a second silicon lid wafer to the device wafer, further utilizing a standard mode cancellation to decrease errors from process variation, temperature, and environmental stress. The KX134-1211 also features an advanced Wake-Up and Back-to-Sleep detection with a high-resolution threshold capability configurable down to 15.6mg, 512-byte buffer that continues to record data even when being read, as well as embedded engines for orientation, directional/double-tap, and free-fall detection. Accel 20 Click allows the use of both I2C and SPI interfaces with a maximum frequency of 3.4MHz for I2C and 10MHz for SPI communication. The selection can be made by positioning SMD jumpers labeled COMM SEL in an appropriate position. Note that all the jumpers' positions must

be on the same side, or the Click board™ may become unresponsive. While the I2C interface is selected, the KX134-1211 allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled ADDR SEL. The Accel 20 also possesses two interrupts, I1 and I2, routed to the INT and AN pins on the mikroBUS™ used to signal MCU that an event has been sensed, and one trigger pin labeled as TRG, routed to the PWM pins on the mikroBUS™ socket, used for FIFO buffer control. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Accel 20 Click top side image
Accel 20 Click bottom side image

Features overview

Development board

Fusion for ARM 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 ARM® Cortex®-M based MCUs 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 ARM v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the Fusion for ARM 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 ARM 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 ARM v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Interrupt 2
SPI Chip Select
SPI Clock
Power Supply
FIFO Control Trigger
Interrupt 1
I2C Clock
I2C Data

Take a closer look


Accel 20 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 ARM 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 Accel 20 Click driver.

Key functions:

  • accel20_get_axis_data - Accel 20 get accelerometer axis function

  • accel20_set_output_data_rate - Accel 20 set output data rate function

  • accel20_set_accel_range - Accel 20 set accel range function

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 main.c
 * @brief Accel20 Click example
 * # Description
 * This library contains API for Accel 20 Click driver.
 * The library initializes and defines the I2C or SPI bus drivers 
 * to write and read data from registers. 
 * The library also includes a function for reading X-axis, Y-axis, and Z-axis data. 
 * The demo application is composed of two sections :
 * ## Application Init
 * The initialization of I2C or SPI module, log UART, and additional pins. 
 * After the driver init, the app executes a default configuration,
 * checks communication and device ID. 
 * ## Application Task
 * This is an example that demonstrates the use of the Accel 20 Click board™.
 * Measures and displays acceleration data for X-axis, Y-axis, and Z-axis. 
 * Results are being sent to the USART terminal where the user can track their changes. 
 * This task repeats every 1 sec.
 * @author Nenad Filipovic

#include "board.h"
#include "log.h"
#include "accel20.h"

static accel20_t accel20;
static log_t logger;

void application_init ( void )
    log_cfg_t log_cfg;          /**< Logger config object. */
    accel20_cfg_t accel20_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.
    accel20_cfg_setup( &accel20_cfg );
    ACCEL20_MAP_MIKROBUS( accel20_cfg, MIKROBUS_1 );
    err_t init_flag  = accel20_init( &accel20, &accel20_cfg );
    if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) )
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );

    accel20_default_cfg ( &accel20 );
    log_info( &logger, " Application Task " );
    log_printf( &logger, "-------------------------\r\n" );
    log_printf( &logger, "      Accel 20 Click     \r\n" );
    log_printf( &logger, "-------------------------\r\n" );
    Delay_ms( 100 ); 
    if ( accel20_check_id( &accel20 ) == ACCEL20_OK ) 
        log_printf( &logger, "     Communication OK    \r\n" );
        log_printf( &logger, "-------------------------\r\n" );
        log_printf( &logger, "   Communication ERROR   \r\n" );
        log_printf( &logger, "     Reset the device    \r\n" );
        log_printf( &logger, "-------------------------\r\n" );

        for ( ; ; );
    log_printf( &logger, "       Accel Data:       \r\n" );
    log_printf( &logger, "-------------------------\r\n" );
    Delay_ms( 100 ); 

void application_task ( void )
    static accel20_axis_t axis;
    if ( accel20_get_int_1( &accel20 ) == ACCEL20_INT1_DATA_READY )
        accel20_get_axis_data( &accel20, &axis );
        log_printf( &logger, "\tX : %d \r\n\tY : %d \r\n\tZ : %d \r\n", axis.x, axis.y, axis.z );
        log_printf( &logger, "-------------------------\r\n" );
        Delay_ms( 1000 );     
    Delay_ms( 1 );  

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support