Determine the magnetic field orientation using the AS5600 and ATmega328P

Be sure you are in the correct position

Published Feb 14, 2024

Click board™

Angle 7 Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Find the magnet's absolute angular position

Hardware Overview

How does it work?

Angle 7 Click is based on the AS5600, an easy-to-program magnetic rotary position sensor with a high-resolution 12-bit analog or PWM output from ams AG. The AS5600 is a Hall-based rotary magnetic position sensor using planar sensors that convert the magnetic field component perpendicular to the surface of the chip into a voltage. It measures the absolute angle of a diametric-magnetized on-axis magnet while at the same time rejecting stray magnetic fields. By default, the output represents a range from 18 to 360 degrees. It is also possible to define a smaller range to the output by programming a zero angle (start position) and a maximum angle (stop position). First, the signals coming from internal Hall sensors are amplified and filtered before their conversion by the ADC and then processed by the hardwired CORDIC block to compute the angle and magnitude of the magnetic field vector. The intensity of the magnetic field is used by the

automatic gain control (AGC) to adjust the amplification level to compensate for temperature and magnetic field variations. After that, the output stage uses the angle value provided by the CORDIC algorithm. The user can choose between an analog output representing the angle as a ratiometric linear absolute value and a digital PWM-encoded output representing the angle as the pulse width. The selection can be made by positioning the SMD jumper labeled OUT SEL in an appropriate position marked as AN or INT. Angle 7 Click communicates with MCU using the standard I2C 2-Wire interface with a maximum clock frequency of 1MHz, fully adjustable through software registers. Also, the DIR SEL jumper allows users to select the polarity of the output relative to rotation direction by positioning the SMD jumper in an appropriate position marked as CW or CCW allowing clockwise or counterclockwise rotation. A unique addition to this board

is a position for a Rotary Magnet Holder designed to be used alongside a magnetic rotary position sensor allowing fast prototyping and quick measurements during development. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Both mikroBUS™ power rails have protection in the form of diode MAX40200, controllable through an EN pin on the mikroBUS™ socket to prevent any unwanted back voltage. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development. In the case of using a logic level of 5V, it is necessary first to remove the resistor R6 and then switch the VCC jumper to the 5V position.

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)

Silicon Vendor

Microchip

Pin count

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.

Rotary Magnetic Holder is an addition designed for use alongside a magnetic rotary position sensor. It comes with a plastic stand measuring 22x16x10 millimeters (L x W x H), as well as an adjustable shaft with a 6mm diameter magnet. The plastic frame has four round feet that fit into holes in the board near the magnetic rotary position sensor, with a 6mm diameter hole on top to match the adjustable shaft that carries the magnet. This shaft has a height adjustment screw on it, allowing the user to adjust it between 18 and 22 millimeters. This way, fast prototyping and quick measurements of the magnet characteristics are allowed during development.

Used MCU Pins

mikroBUS™ mapper

Analog Signal

PC0

RST

Enable

PB2

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

PWM Signal

PC3

INT

I2C Clock

PC5

SCL

I2C Data

PC4

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Click Shield for Arduino UNO front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.

Arduino UNO Rev3 front image hardware assembly

Charger 27 Click front image hardware assembly

Charger 27 Click complete accessories setup image hardware assembly

Arduino UNO Rev3 Access MB 1 - upright/background hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step 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 Angle 7 Click driver.

Key functions:

angle7_get_status This function reads the status data.
angle7_get_angle This function reads the calculated angle in degrees.
angle7_get_magnitude This function reads the magnitude data.

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 Angle7 Click example
 *
 * # Description
 * This example demonstrates the use of Angle 7 click board by reading and displaying
 * the magnet's angular position in degrees and analog voltage output as well as
 * the magnet's status and magnitude.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration.
 *
 * ## Application Task
 * Reads the magnet's angular position in degrees and analog voltage output 
 * as well as the magnet's status and magnitude and displays the results on the USB UART
 * approximately every 100ms.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "angle7.h"

static angle7_t angle7;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    angle7_cfg_t angle7_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.
    angle7_cfg_setup( &angle7_cfg );
    ANGLE7_MAP_MIKROBUS( angle7_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == angle7_init( &angle7, &angle7_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( ANGLE7_ERROR == angle7_default_cfg ( &angle7 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    float voltage, raw_angle, angle;
    uint16_t magnitude;
    uint8_t status;
    if ( ADC_ERROR != angle7_read_an_pin_voltage ( &angle7, &voltage ) ) 
    {
        log_printf( &logger, " AN voltage: %.3f V\r\n", voltage );
    }
    if ( ANGLE7_OK == angle7_get_angle ( &angle7, &angle ) )
    {
        log_printf ( &logger, " Angle: %.2f Degrees\r\n", angle );
    }
    if ( ANGLE7_OK == angle7_get_magnitude ( &angle7, &magnitude ) )
    {
        log_printf ( &logger, " Magnitude: %u\r\n", magnitude );
    }
    if ( ANGLE7_OK == angle7_get_status ( &angle7, &status ) )
    {
        log_printf ( &logger, " Status:" );
        if ( status & ANGLE7_STATUS_MAGNET_DETECTED )
        {
            log_printf ( &logger, " Magnet Detected \r\n Magnet Strength:" );
            if ( status & ANGLE7_STATUS_MAGNET_TOO_STRONG )
            {
                log_printf ( &logger, " Too Strong \r\n\n" );
            }
            else if ( status & ANGLE7_STATUS_MAGNET_TOO_WEAK )
            {
                log_printf ( &logger, " Too Weak \r\n\n" );
            }
            else
            {
                log_printf ( &logger, " Good \r\n\n" );
            }
        }
        else
        {
            log_printf ( &logger, " Magnet Not Detected \r\n\n" );
        }
    }
    Delay_ms ( 100 );
}

void main ( void ) 
{
    application_init( );

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

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