Monitor and respond to changes in the magnetic environment with US2882 and MK64FN1M0VDC12
Add a bipolar hall switch for smoother operations
Published Jun 20, 2023
Click board™
Bi Hall Click
Dev Board
Clicker 2 for Kinetis
Compiler
NECTO Studio
MCU
MK64FN1M0VDC12
By incorporating a bipolar Hall switch solution, you can ensure seamless switching between different states or modes in your design, enhancing its functionality and versatility
A
A
Hardware Overview
How does it work?
BI HALL Click is based on the US2882, a bipolar Hall-effect switch designed in mixed signal CMOS technology from Melexis Technologies. The US2882 comes with very high magnetic sensitivity based on mixed-signal CMOS technology. The US2882 integrates a voltage regulator, a Hall sensor with a dynamic offset cancellation system, a Schmitt trigger, and an open-drain output driver, all in a single package. It allows using generic magnets, weak magnets, or more significant air gaps, making it suitable for various automotive, consumer, and BLDC motor applications. The US2882 exhibits bipolar magnetic switching characteristics. Therefore, it operates with both the South and North poles. Typically, the device
behaves as a latch with symmetric operating and release switching points, which means magnetic fields with equivalent strength and opposite directions drive the output HIGH and LOW. In this way, it is possible to determine the pole of the magnet using the information that the host MCU receives from the sensor via the INT line of the mikroBUS™ socket. It is also possible to visually identify the magnet's North Pole via an onboard red LED. Removing the magnetic field keeps the output in its previous state, which defines the US2882 as a magnetic memory. Depending on the magnetic switching points, the US2882 may also behave as a unipolar positive or negative switch, which means the output can be set to HIGH and LOW by only
using one magnetic pole. In such a case, removing the magnetic field changes the output level. The chopper-stabilized amplifier uses a switched-capacitor technique to suppress the offset generally observed with Hall sensors and amplifiers. The CMOS technology makes this advanced technique possible, resulting in more stable magnetic characteristics. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the LOGIC LEVEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. 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.
Features overview
Development board
Clicker 2 for Kinetis is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit ARM Cortex-M4F microcontroller, the MK64FN1M0VDC12 from NXP Semiconductors, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a JTAG programmer connector, and two 26-pin headers for interfacing with external electronics. Its compact design with clear and easily recognizable silkscreen markings allows you to build gadgets with unique functionalities and
features quickly. Each part of the Clicker 2 for Kinetis development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the Clicker 2 for Kinetis programming method, using a USB HID mikroBootloader or an external mikroProg connector for Kinetis programmer, the Clicker 2 board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Micro-B cable, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or
using a Li-Polymer battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several user-configurable buttons and LED indicators. Clicker 2 for Kinetis is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping 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
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
NXP
Pin count
121
RAM (Bytes)
262144
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Clicker 2 for Kinetis as your development board.
Track your results in real time
Application Output
After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.
After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.
Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.
Software Support
Library Description
This library contains API for BI HALL Click driver.
Key functions:
bihall_det_mag_field- Detecting south and north pole magnetic fields status function
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 BI HALL Click example
*
* # Description
* Detect the south & north pole magnetic fields.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Configuring clicks and log objects.
*
* ## Application Task
* This is a example which demonstrates the use of BI HALL Click board.
* Detect the south & north pole magnetic fields near the BI HALL Click.
* Results are being sent to the Usart Terminal where you can track their changes.
* All data logs on usb uart when magnetic field is detected.
*
* \author Nenad Filipovic
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "bihall.h"
// ------------------------------------------------------------------ VARIABLES
static bihall_t bihall;
static log_t logger;
uint8_t bihall_state;
uint8_t bihall_state_old;
// ------------------------------------------------------- ADDITIONAL FUNCTIONS
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
bihall_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_printf(&logger, "---- Application Init ----\r\n");
// Click initialization.
bihall_cfg_setup( &cfg );
BIHALL_MAP_MIKROBUS( cfg, MIKROBUS_1 );
bihall_init( &bihall, &cfg );
log_printf(&logger, " Detecting magnetic fields\r\n");
log_printf(&logger, "--------------------------\r\n");
bihall_state = BIHALL_MAG_POLE_NORTH;
bihall_state_old = BIHALL_MAG_POLE_NORTH;
}
void application_task ( void )
{
bihall_state = bihall_det_mag_field( &bihall );
if ( ( bihall_state == BIHALL_MAG_POLE_SOUTH ) && ( bihall_state_old == BIHALL_MAG_POLE_NORTH ) )
{
bihall_state_old = BIHALL_MAG_POLE_SOUTH;
log_printf(&logger, " ~ SOUTH ~\r\n");
log_printf(&logger, "--------------------------\r\n");
}
if ( ( bihall_state == BIHALL_MAG_POLE_NORTH ) && ( bihall_state_old == BIHALL_MAG_POLE_SOUTH ) )
{
log_printf(&logger, " ~ NORTH ~\r\n");
log_printf(&logger, "--------------------------\r\n");
bihall_state_old = BIHALL_MAG_POLE_NORTH;
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
