Achieve distance and angular measurements for position determination in 3D environments with AK09970N and PIC18LF45K22
Spin the world with 3D Hall magic!
Published Sep 16, 2023
Click board™
3D Hall 7 Click
Dev. board
EasyPIC v8
Compiler
NECTO Studio
MCU
PIC18LF45K22
Discover how these sensors can revolutionize navigation, robotics, and beyond, making your devices smarter and more efficient than ever before
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Hardware Overview
How does it work?
3D Hall 7 Click is based on the AK09970N, a low power 3D magnetic sensor from AKM Semiconductor. This sensor relies on a Hall effect to accurately sense magnetic field changes on three perpendicular axes. The internal magnetic field sensing elements are multiplexed and connected to a pre-amplifier and then to a 16-bit low noise Analog to Digital Converter (ADC), which sequentially samples each sensor, providing 16-bit spatial data over the digital interface. The magnetic sensor has a very low pin count. Therefore, SPI and I2C lines are multiplexed on the same pins. In order to allow functionality for both SPI and I2C interfaces, 3D Hall 7 click have onboard jumpers for communication interface selection. Thus, the communication interface selection procedure relies on switching the appropriate SMD jumpers, named COMM SEL. Note that all of the I2C/SPI group jumpers need to be switched at the same side: all three should either be soldered as I2C or SPI. If one of them shows in the opposite position from the rest, the communication with the IC might not be possible. The power consumption is a big concern as of lately, with the introduction of the IoT. The ability to work in a low power mode is a must for every device which is to be used for any type of IoT
networking. The AK09970N magnetic sensor features power down mode, single measurement mode and seven continuous measurement modes, allowing the user to make a perfect balance between sampling frequency, measurement accuracy and power consumption. The power consumption is in a close relationship with the data output refresh rate (ODR). The AK09970N magnetic sensor also features a powerful programmable interrupt engine, which allows many event sources to be signaled via the two interrupt pins (INT and ODINT), which are routed from the sensor to the mikroBUS™ INT and AN pins respectively. A very useful function of the interrupt engine is the signaling of the data ready event. That way, the host MCU does not have to poll the sensor for the data acquisition. The sensor can simply trigger an interrupt when the data is ready for reading. The interrupt engine allows some other customizations of the interrupt signal, such as the magnetic sensor overflow, ADC overflow and Switch event. The 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 IC is equipped with the temperature independent reference voltage, thus minimizing the influence the mentioned unwanted factors. The power mode, output data rate, interrupt thresholds for each axis, and other working parameters, including the availability of the I2C interface, are contained within the configuration registers of the AK09970N magnetic sensor. The sensor is highly configurable, with many configuration options. The AK09970N datasheet contains an in-depth explanation of all the registers and their functionality. However, 3D Hall 7 software library contains simplified functions that allow straight-forward readings to be performed, reducing the steps needed for a proper initialization and configuration of the device. 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
EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. 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, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any
circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board 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 DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC 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
Architecture
PIC
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
1536
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 EasyPIC v8 as your development board.
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 3D Hall 7 Click driver.
Key functions:
c3dhall7_get_axis_data- Get Axis data functionc3dhall7_get_status- Measurement status functionc3dhall7_get_status- Measurement status function.
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 3dHall7 Click example
*
* # Description
* Read the position of magnetic
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes driver init, test communication and configuration device for measurement.
*
* ## Application Task
* Reads 3 Axis of the magnetic sensor and logs this data to USBUART every 500ms.
*
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "c3dhall7.h"
// ------------------------------------------------------------------ VARIABLES
static c3dhall7_t c3dhall7;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( )
{
c3dhall7_dev_info_t info;
uint8_t red_data;
log_cfg_t log_cfg;
c3dhall7_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.
c3dhall7_cfg_setup( &cfg );
C3DHALL7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
c3dhall7_init( &c3dhall7, &cfg );
c3dhall7_device_reset( &c3dhall7 );
// Test communication
c3dhall7_device_info( &c3dhall7, &info );
if ( info.device_id == C3DHALL7_DEVICE_ID )
{
log_printf( &logger, "---- Communication [ OK ]!!! ----\r\n" );
}
else
{
log_printf( &logger, "---- Communication [ ERROR ]!!! ----\r\n" );
for ( ; ; );
}
// Configuration
c3dhall7_default_cfg ( &c3dhall7 );
}
void application_task ( void )
{
c3dhall7_axis_t axis;
c3dhall7_get_axis_data( &c3dhall7, &axis );
log_printf( &logger, "---- Measurement data of magnetic sensor ----\r\n" );
log_printf( &logger, "X axis: %d \r\n", axis.x );
log_printf( &logger, "Y axis: %d \r\n", axis.y );
log_printf( &logger, "Z axis: %d \r\n", axis.z );
log_printf( &logger, "---------------------------------------------\r\n");
Delay_ms( 500 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
