Intermediate
30 min

Unlock a new realm of possibilities with 3D acceleration technology thanks to the ADXL373 and PIC18F26K42

Lead the way in motion sensing

Accel 27 Click with EasyPIC v7

Published Dec 29, 2023

Click board™

Accel 27 Click

Development board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18F26K42

Achieve precision in every direction with our 3-axis accelerometer, revolutionizing how we perceive and utilize motion data

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Hardware Overview

How does it work?

Accel 27 Click is based on the ADXL373, a complete three-axis ±400g acceleration measurement system from Analog Devices, operating at extremely low power levels. Built-in digital logic enables autonomous operation and implements functions that enhance system-level power savings. It offers 12-bit output data at 200mg/LSB scale factor, reporting acceleration digitally through a configurable and selectable serial interface. The ADXL373 has three operating modes. Measurement mode is used for continuous, broad bandwidth sensing. The wake-up mode is used for limited bandwidth low g activity detection, and the instant-on mode is

used for low power impact detection. Measurement can be suspended entirely by placing the ADXL373 in Standby mode. As mentioned, the acceleration data is accessed through the I2C or SPI interface with a maximum frequency of 3.4MHz for I2C and 10MHz for SPI communication. The selection is 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 ADXL373 allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled ADDR SEL.

This board also possesses two interrupts, IT1 and IT2, routed to, where, by default, the INT and AN pins stand on the mikroBUS™ socket, entirely programmed by the user through a serial interface. They signal MCU that a motion event has been sensed. 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 27 Click top side image
Accel 27 Click bottom side image

Features overview

Development board

EasyPIC v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. 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, EasyPIC v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of

the EasyPIC 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 various external power sources, including an external 12V power supply, 7-23V AC or 9-32V 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. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC 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.

EasyPIC v7 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

4096

Used MCU Pins

mikroBUS™ mapper

Interrupt 2
RA3
AN
NC
NC
RST
SPI Chip Select
RA5
CS
SPI Clock
RC3
SCK
SPI Data OUT
RC4
MISO
SPI Data IN
RC5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt 1
RB1
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
2

Take a closer look

Schematic

Accel 27 Click Schematic schematic

Step by step

Project assembly

EasyPIC v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7 as your development board.

EasyPIC v7 front image hardware assembly
Rotary B 2 Click front image hardware assembly
MCU DIP 28 hardware assembly
EasyPIC v7 MB 2 - 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 DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step 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 27 Click driver.

Key functions:

  • accel27_get_int1_pin - This function returns the interrupt 1 (INT1) pin logic state

  • accel27_get_axes - This function reads accel X, Y, and Z axis data in g

  • accel27_reset_device - This function performs the chip software reset

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 Accel 27 Click example
 *
 * # Description
 * This example demonstrates the use of Accel 27 click board by reading and displaying 
 * the accelerometer data (X, Y, and Z axis) averaged from 100 samples.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration.
 *
 * ## Application Task
 * Reads and displays on the USB UART the accelerometer data (X, Y, and Z axis) averaged from 100 samples.
 *
 * @note
 * This click board should be used for high g applications of up to +-400g. It is not recommended
 * for low g applications because of its high scale factor which is about 200 mg per LSB.
 * 
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "accel27.h"

// The number of data samples for averaging
#define NUM_OF_SAMPLES  100

static accel27_t accel27;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    accel27_cfg_t accel27_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.
    accel27_cfg_setup( &accel27_cfg );
    ACCEL27_MAP_MIKROBUS( accel27_cfg, MIKROBUS_1 );
    err_t init_flag = accel27_init( &accel27, &accel27_cfg );
    if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( ACCEL27_ERROR == accel27_default_cfg ( &accel27 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    accel27_axes_t axes = { 0 };
    uint16_t cnt = 0;
    while ( cnt < NUM_OF_SAMPLES )
    {
        // Wait for data ready indication
        while ( !accel27_get_int1_pin ( &accel27 ) );

        accel27_axes_t tmp_axes;
        if ( ACCEL27_OK == accel27_get_axes ( &accel27, &tmp_axes ) )
        {
            axes.x += tmp_axes.x;
            axes.y += tmp_axes.y;
            axes.z += tmp_axes.z;
            cnt++;
        }
    }
    axes.x = axes.x / NUM_OF_SAMPLES;
    axes.y = axes.y / NUM_OF_SAMPLES;
    axes.z = axes.z / NUM_OF_SAMPLES;
    log_printf( &logger, " X: %.1f g\r\n", axes.x );
    log_printf( &logger, " Y: %.1f g\r\n", axes.y );
    log_printf( &logger, " Z: %.1f g\r\n\n", axes.z );
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources