Provide seamless touch detection and precise magnetic field sensing with IQS624 and STM32F091RC
Connect with a single touch
Published Feb 26, 2024
Click board™
ProxFusion Click
Dev Board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Designed to enhance user interaction and control, this advanced sensor device empowers developers to create innovative products with touch-sensitive capabilities and accurate magnetic angle detection
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Hardware Overview
How does it work?
ProxFusion Click is based on the IQS624, a combined multi-sensor IC from Azoteq, including Hall-effect rotation sensing, dual-channel capacitive proximity or touch sensing, or single-channel inductive sensing. This IC features the proven ProxSense® engine, and it has many on-chip features that are used to process the sensor data, such as calculated angle rotation with 1° precision, Automatic Tuning Implementation (ATI), relative rotation angle, and more. All these functions process the sensor data before the final result is sent to the output in a human-understandable format. Besides these processed values, IQS624 can also send raw values on the output so that external processing can be applied. The board's design is reasonably simple since the IC encompasses all the required components on the chip. The I2C bus lines are pulled up to 3.3V with the resistors and the RDY pin from the IC, routed to the INT pin of the mikroBUS™. This pin can report an event when the device is set to work in the event mode via I2C. Otherwise, this pin is
used to indicate a communication window. After the host MCU initializes the communication by sending the valid I2C address of the IQS624 IC, it will respond with the ACK signal, and the RDY pin will be pulled to a LOW logic state to indicate an open communication window. I2C features a time-out that will reset the communication bus and the RDY pin, allowing MCU to use interrupts and break the I2C ACK signal polling loop. The capacitive touch sensing is accomplished by two onboard pads routed to two internal channels of the IQS624 sensor IC. All the calibration can be automatically done by writing to the corresponding ATI registers. This group of registers also contains settings for the capacitive touch threshold and the proximity threshold, as well as some additional general configuration settings for these sensors. Both of these channels can be configured independently. The other four channels of the IQS624 sensor are routed to the outputs of two on-chip Hall plates, which are used to detect a magnetic field rotation. The Hall-effect magnetic field measurement is a
measurement of the current through the Hall-effect sensor plates, generated by the magnetic field penetrating through each plate perpendicularly. Channels 2 and 4 are used to measure positive direction, while channels 3 and 5 are used to measure negative direction. The IC can use the differential data to provide the Hall-effect rotation UI element angle - or a magnet rotation angle, parallel to the click board™ surface. The raw input from the sensors is processed so it outputs comprehensible information at the output. Corresponding registers can be set to configure and receive the data from Hall-effect sensors. The working frequency of the device is 16MHz, and the maximum I2C clock speed is 400kHz. ProxFusion click can work in several different power-saving modes, depending on the design requirements. As explained above, the event mode can be set within the configuration registers. Otherwise, a streaming mode is active by default, and the information can be obtained whenever the RDY is triggered.
Features overview
Development board
Nucleo-64 with STM32F091RC MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M0
MCU Memory (KB)
256
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
32768
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 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 STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
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 Nucleo-64 with STM32F091RC MCU as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for ProxFusion Click driver.
Key functions:
proxfusion_get_touch- This function detects touch eventproxfusion_set_system_reg- This function sets system registerproxfusion_set_event_reg- This function select events
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 ProxFusion Click example
*
* # Description
* This demo-app reads and displays touch events using ProxFusion click.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Configuring clicks and log objects.
* Settings the click in the default configuration.
*
* ## Application Task
* Checks if a new touch event occurred and prints(logs) event message on usbuart.
*
* \author Katarina Perendic
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "proxfusion.h"
// ------------------------------------------------------------------ VARIABLES
static proxfusion_t proxfusion;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
proxfusion_cfg_t proxfusion_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.
proxfusion_cfg_setup( &proxfusion_cfg );
PROXFUSION_MAP_MIKROBUS( proxfusion_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == proxfusion_init( &proxfusion, &proxfusion_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( PROXFUSION_ERROR == proxfusion_default_cfg ( &proxfusion ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
uint8_t touch = proxfusion_get_touch( &proxfusion );
if ( 1 == touch )
{
log_printf( &logger, " Touch button 1 is pressed\r\n" );
}
else if ( 2 == touch )
{
log_printf( &logger, " Touch button 2 is pressed\r\n" );
}
else if ( 3 == touch )
{
log_printf( &logger, " Both touch buttons are pressed\r\n" );
}
Delay_ms ( 100 );
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
