Provide real-time location-based information and interactive experiences with AK09915 and ATmega328P
Discover true North
Published Feb 14, 2024
Click board™
Compass 4 Click
Dev Board
Arduino UNO Rev3
Compiler
NECTO Studio
MCU
ATmega328P
Achieve high-precision three-axis magnetic field measurements, allowing for accurate positioning and orientation sensing in various applications
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Hardware Overview
How does it work?
Compass 4 Click is based on the AK09915, a complete 3-axis magnetic sensor with signal processing from AKM. The AK09915 incorporates magnetic sensors for detecting terrestrial magnetism in the X-axis, Y-axis, and Z-axis, a sensor driving circuit, a signal amplifier chain, and an arithmetic circuit for processing the signal from each sensor. The output signal of each axis sensor is multiplexed, pre-amplified, processed, and digitized by a 16-bit A/D converter (ADC). A three-axis magnetometer can be programmed to measure the magnetic component for each axis within the full-scale range of ±4912 μT and sensitivity of 0.15 µT per LSB. The AK09915 has an analog circuit, digital logic, and interface block integrated into a chip. It also supports nine different Operation Modes that can be chosen by setting the appropriate registers. When the Single
Measurement Mode is set, the magnetic sensor measurement starts. After magnetic sensor measurement and signal processing are finished, measured magnetic data is stored in measurement data registers, and then the AK09915 transits to Power-Down Mode automatically. On transition to Power-Down Mode, the Data Ready (DRDY) bit turns to “1”. When any measurement data registers are read, the DRDY bit turns to “0”. It remains “1” on the transition from Power-Down Mode to another Mode. The Ready output pin of the AK09915 labeled as the DRY is routed to the INT pin of the mikroBUS™ socket. Besides the Data Ready pin, this Click board™ also has the Reset pin (RST), routed to the appropriate position on the mikroBUS™. Compass 4 Click allows for both I2C and SPI interfaces with a maximum frequency of 2.5MHz for I2C and 4MHz
for SPI communication. The selection can be performed by positioning SMD jumpers labeled COMM SEL to an appropriate position. Note that all the jumpers must be placed on the same side, or the Click board™ may become unresponsive. While the I2C interface is selected, the AK09915 allows the choice of the last two significant bits (LSB) of its I2C slave address. This can be done by using the SMD jumper labeled as ADDR SEL. Four different addresses can be set depending on the positions of each of the ADDR SEL jumpers. 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.
Features overview
Development board
Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an
ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the
first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
2048
You complete me!
Accessories
Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.
Track your results in real time
Application Output
This Click board can be interfaced and monitored in two ways:
Application Output- Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.
UART Terminal- Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.
Software Support
Library Description
This library contains API for Compass 4 Click driver.
Key functions:
compass4_get_interrupt- Gets INT pin state (DRDY pin)compass4_get_single_axis- Gets single axis valuecompass4_get_magnetic_flux- Gets magnetic flux of X\Y\Z axis value
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
* \brief Compass4 Click example
*
* # Description
* This demo application measures magnetic flux data.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and resets the module, then checks
* the communication with the module and sets the module default configuration.
*
* ## Application Task
* Reads magnetic flux data and displays the values of X, Y, and Z axis to
* the USB UART each second.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "compass4.h"
// ------------------------------------------------------------------ VARIABLES
static compass4_t compass4;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
compass4_cfg_t cfg;
uint8_t device;
/**
* 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.
compass4_cfg_setup( &cfg );
COMPASS4_MAP_MIKROBUS( cfg, MIKROBUS_1 );
compass4_init( &compass4, &cfg );
compass4_hardware_reset( &compass4 );
Delay_ms( 500 );
device = compass4_check_device( &compass4 );
if ( device == 0 )
{
log_printf( &logger, ">> Device communication [ OK ] \r\n" );
}
else
{
log_printf( &logger, ">> Device communication [ ERROR ] \r\n" );
for ( ; ; );
}
compass4_configuration ( &compass4, COMPASS4_CTRL1_WM_STEPS_5 |
COMPASS4_CTRL1_NOISE_ENABLE,
COMPASS4_CTRL2_MODE_CONT_1 |
COMPASS4_CTRL2_SDR_LOW_NOISE |
COMPASS4_CTRL2_FIFO_ENABLE );
log_printf( &logger, ">> Start measurement \r\n" );
}
void application_task ( void )
{
compass4_flux_t flux;
uint8_t err;
err = compass4_get_magnetic_flux( &compass4, &flux );
if ( err != 0 )
{
log_printf( &logger, ">> Measurement error \r\n" );
}
else
{
log_printf( &logger, ">> Magnetic flux data << \r\n" );
log_printf( &logger, ">> X: %.2f \r\n", flux.x );
log_printf( &logger, ">> Y: %.2f \r\n", flux.y );
log_printf( &logger, ">> Z: %.2f \r\n", flux.z );
}
log_printf( &logger, "-----------------------------\r\n" );
Delay_ms( 1000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
