Create contactless switches for applications where physical contact is impractical or undesirable with NMH1000 and PIC18F86K22
Hall-effect magnetic switch
Published Jan 23, 2024
Click board™
Hall Switch 3 Click
Dev Board
UNI-DS v8
Compiler
NECTO Studio
MCU
PIC18F86K22
Detect changes in vertical magnetic fields and achieve unparalleled sensitivity to specific magnet orientations
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Hardware Overview
How does it work?
Hall Switch 3 Click is based on the NMH1000, a Hall-effect magnetic switch from NXP Semiconductor. The switch processes its input over the functional blocks that consist of a configurable state machine, an analog-to-voltage conversion of the input, and a comparison to generate the bi-state output. The output is arranged in a linear succession. The NMH1000 has a transducer that generates a small charge proportional to the
proximal magnetic flux density. The Hall-effect charge is converted to voltage and compared with the pre-defined threshold voltage. This determines the state of the switch's output. Hall Switch 3 Click uses a standard 2-wire I2C interface to communicate with the host MCU, supporting a clock frequency of up to 1MHz. The output of the switch, according to the pre-defined threshold, is available over the output OUT pin. 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
UNI-DS v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different STM32, Kinetis, TIVA, CEC, MSP, PIC, dsPIC, PIC32, and AVR MCUs regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. 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, UNI-DS v8 provides a fluid and immersive working experience, allowing access anywhere and under any
circumstances at any time. Each part of the UNI-DS v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it 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
HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. UNI-DS 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
Type
8th Generation
Architecture
PIC
MCU Memory (KB)
64
Silicon Vendor
Microchip
Pin count
80
RAM (Bytes)
3862
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 UNI-DS v8 as your development board.
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.
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.
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".
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.
Software Support
Library Description
This library contains API for Hall Switch 3 Click Click driver.
Key functions:
hallswitch3_get_mag_data- This function is used to indicates a relative magnetic field strength.hallswitch3_set_out_data_rate- This function provides the capability for the user to override the fixed sample rate controlling the sleep-compare-Vout cycle time.hallswitch3_get_status- This function reads a status reporting of modes and selections.
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 main.c
* @brief Hall Switch 3 Click example
*
* # Description
* This example demonstrates the use of Hall Switch 3 Click board
* by reading and displaying the magnetic field strength value.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization of I2C module and log UART.
* After driver initialization, the app executes a default configuration.
*
* ## Application Task
* This example demonstrates the use of the Hall Switch 3 Click board.
* The demo application reads and displays the relative magnetic field strength value [Gaussian units]
* and detects when the magnetic field strength is not in the configured range.
* The results are sent to the UART terminal, where you can monitor their changes.
*
* @author Nenad Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "hallswitch3.h"
static hallswitch3_t hallswitch3;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
hallswitch3_cfg_t hallswitch3_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.
hallswitch3_cfg_setup( &hallswitch3_cfg );
HALLSWITCH3_MAP_MIKROBUS( hallswitch3_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == hallswitch3_init( &hallswitch3, &hallswitch3_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( HALLSWITCH3_ERROR == hallswitch3_default_cfg ( &hallswitch3 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
int8_t mag_data = 0;
if ( HALLSWITCH3_OK == hallswitch3_get_mag_data( &hallswitch3, &mag_data ) )
{
log_printf( &logger, " Magnetic Field: %d [Gs]\r\n", ( int16_t ) mag_data );
if ( HALLSWITCH3_OUT_STATE_LOW == hallswitch3_check_mag_field( &hallswitch3 ) )
{
log_printf( &logger, " The switch is open.\r\n" );
}
}
Delay_ms( 1000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
