Intermediate
30 min
0

Provide a comprehensive view of magnetic fields in three dimensions using TLV493D-A1B6 and PIC18F46K80

Tri-axis magnetic field sensing

3D Hall 2 click with EasyPIC v7

Published Nov 01, 2023

Click board™

3D Hall 2 click

Development board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18F46K80

Explore our cutting-edge solution that senses magnetic field strength along three perpendicular axes, delivering unrivaled accuracy for a wide range of applications

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Hardware Overview

How does it work?

3D Hall 2 Click is based on the TLV493D-A1B6, a low power 3D magnetic sensor, from Infineon. This sensor relies on a Hall effect to accurately sense magnetic field changes on three perpendicular axes. The internal sensing elements are spinning Hall sensor plates, connected to a 12bit low noise Analog to Digital Converter (ADC), which sequentially samples each sensor, providing 12-bit spatial data over the I2C interface. An additional 8-bit thermal sensor is also available, and it is used for the thermal compensation. The magnetic sensor has very low pin count (only 6), packed in a SOP6 casing. Therefore, the I2C interface is used for the reset too, while the interrupt pin is multiplexed with the I2C clock line. The interrupt is a useful feature which is used to signal a data ready event to the host microcontroller. For more robust data transfer, the device also contains a frame counter, which increases after each sensor sampling cycle. If the cycle was stopped for whatever reason, the frame counter will indicate this problem, and the application is able to take the necessary steps. Parity Error Check mechanism is also implemented for even more

data transfer robustness. Sensor provides raw data output, based on a strength of the magnetic field. The measurement is affected by many factors: slight manufacturing differences between ICs affect the readings, even the slight differences between Hall plates within the same IC might affect the accuracy, although the IC contains highly matched sensing elements. Also, the altitude might affect the readings, as well as temperature changes. Therefore, the sensor IC is equipped with the thermal sensor, used to measure influence of the ambient temperature. Unlike errors which occur as the result due to influence of other elements, the thermal influence is not linear and therefore, the host firmware should utilize a Look-up Table (LUT) for several thermal values, in order to achieve linear response. The thermal sensor allows reducing the error margin of the angle measurement from ±2˚ to ±3˚ by using such LUT table compensation. The datasheet contains the whole calibrating procedure, as well as the angle calculation based on raw sensor data, as well as formulas for conversion the thermal and the magnetic data.

There are two configuration registers, used to set the working parameters. The interrupt functionality, thermal sensor availability, the power mode, I2C interface speed, data parity test, and other working parameters are contained within two configuration registers, referred to as MOD1 and MOD2 in the datasheet. The I2C address of the device can be changed by overwriting corresponding I2C address bits in these two registers. The I2C slave address is additionally determined at the startup, by sampling the state of the SDA (I2C Serial Data) pin within first 200 µs, after which the address remains fixed until the next reset cycle. I2C pins (SCL and SDA) are routed to the mikroBUS™ of the Click board™ for an easy interfacing with the development system. 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.

3D Hall 2 Click top side image
3D Hall 2 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

40

RAM (Bytes)

3648

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

3D Hall 2 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
Buck 22 Click front image hardware assembly
MCU DIP 40 hardware assembly
EasyPIC v7 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 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 3D Hall 2 Click driver.

Key functions:

  • c3dhall2_read_data - This function reads data from register

  • c3dhall2_get_axis_temp_data - This function gets temperature and axis data

  • c3dhall2_configuration - This function configures the chip for measurement.

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 
 * \brief C3dHall2 Click example
 * 
 * # Description
 * 
 * This application reads X/Y/Z hall axis and temperature data and converts it to
 * human readable format.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initialization driver init and configuration chip
 * 
 * ## Application Task  
 * Reads X/Y/Z hall axis and Temperature data.
 * All data logs on the USBUART every 3 sec.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "c3dhall2.h"

// ------------------------------------------------------------------ VARIABLES

static c3dhall2_t c3dhall2;
static log_t logger;
float xyz_axis[ 3 ];
float temperature;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    c3dhall2_cfg_t cfg;

    /** 
     * 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.

    c3dhall2_cfg_setup( &cfg );
    C3DHALL2_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    c3dhall2_init( &c3dhall2, &cfg );
    c3dhall2_default_cfg( &c3dhall2 );

}

void application_task ( void )
{
    c3dhall2_get_axis_temp_data( &c3dhall2, &xyz_axis[ 0 ], &temperature );

    log_printf( &logger, " Axis X: %.2f mT\r\n", xyz_axis[ 0 ] );
    log_printf( &logger, " Axis Y: %.2f mT\r\n", xyz_axis[ 1 ] );
    log_printf( &logger, " Axis Z: %.2f mT\r\n", xyz_axis[ 2 ] );

    log_printf( &logger, " Temperature: %.2f C\r\n", temperature );

    Delay_ms( 2000 );
}

void main ( void )
{
    application_init( );

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


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

Additional Support

Resources