Measure acceleration in three axis with MXC6655XA and STM32F745ZG

Object's inclination and vibration

Published Mar 03, 2023

Click board™

Accel 24 Click

Dev. board

UNI-DS v8

Compiler

NECTO Studio

MCU

STM32F745ZG

Precise measurements of vibration or shock for a variety of applications

Hardware Overview

How does it work?

Accel 24 Click is based on the MXC6655XA, a highly reliable digital triaxial acceleration from MEMSIC. The MXC6655XA is highly configurable with a programmable acceleration range of ±2g, ±4g, or ±8g based on MEMSIC's proprietary thermal technology built with a 0.18μm standard CMOS process. It contains no moving sensor parts, eliminating field reliability and repeatability issues; no measurable resonance (immunity to vibration), stiction, or detectable hysteresis exists. The MXC6655XA also eliminates the "click" sounds typically heard in ball-based orientation sensors. The MEMS structure

is greater than 200,000g. This sensor provides X/Y/Z axis acceleration signals with a low 0g offset and temperature signals with high accuracy. In addition, it also detects six orientation positions, X/Y shake, and shakes directions. Accel 24 Click communicates with an MCU using the standard I2C 2-Wire interface to read data and configure settings capable of operating in a standard or fast mode of operation. The acceleration signal is provided in 12-bit output resolution. In addition to communication pins, this board also possesses an additional interrupt pin routed to the INT pin

on the mikroBUS™ socket, for orientation and X/Y shake detections. The MXC6655XA allows users to be placed in a Power-Down mode enabled through the I2C interface. This Click board™ can only be operated with a 3.3V logic voltage level. 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

UNI-DS 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 STM32, Kinetis, TIVA, CEC, MSP, PIC, dsPIC, PIC32, and AVR 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, UNI-DS v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the UNI-DS 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. UNI-DS 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.

Microcontroller Overview

MCU Card / MCU

Type

8th Generation

Architecture

ARM Cortex-M7

MCU Memory (KB)

1024

Silicon Vendor

STMicroelectronics

Pin count

144

RAM (Bytes)

327680

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

Interrupt

PD3

INT

I2C Clock

PB8

SCL

I2C Data

PB9

SDA

Ground

GND

Take a closer look

Click board™ 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 UNI-DS v8 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

SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly

Board mapper by product7 hardware assembly

NECTO Compiler Selection Step Image 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 Accel 24 Click driver.

Key functions:

accel24_get_int_pin This function returns the INT pin logic state.
accel24_read_data This function checks the data ready bit, clears it, and then reads the accel (X, Y, Z) and temperature measurements.
accel24_set_full_scale_range This function sets the full-scale range resolution.

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 Accel 24 Click example
 *
 * # Description
 * This example demonstrates the use of Accel 24 Click board by reading and displaying 
 * accel data (X, Y, and Z axis) as well as temperature measurements on the USB UART.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the Click default configuration.
 *
 * ## Application Task
 * Reads and displays the accel data (X, Y, and Z axis) as well as temperature measurements
 * on the USB UART every 100ms approximately.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "accel24.h"

static accel24_t accel24;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    accel24_cfg_t accel24_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.
    accel24_cfg_setup( &accel24_cfg );
    ACCEL24_MAP_MIKROBUS( accel24_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == accel24_init( &accel24, &accel24_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( ACCEL24_ERROR == accel24_default_cfg ( &accel24 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    accel24_data_t meas_data;
    // Wait for data ready indication
    while ( accel24_get_int_pin ( &accel24 ) );
    
    if ( ACCEL24_OK == accel24_read_data ( &accel24, &meas_data ) )
    {
        log_printf( &logger, " X: %.3f g\r\n", meas_data.x );
        log_printf( &logger, " Y: %.3f g\r\n", meas_data.y );
        log_printf( &logger, " Z: %.3f g\r\n", meas_data.z );
        log_printf( &logger, " Temperature: %.2f degC\r\n", meas_data.temperature );
    }
    Delay_ms ( 100 );
}

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