Experience unparalleled angle detection with MA735 and STM32F091RC
Magnet's whisper: Revealing angles in style!
Published Feb 26, 2024
Click board™
Magneto 14 Click
Dev Board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Your quest for precise angle information ends here – our solution, powered by magnetic insight, is your go-to tool for obtaining accurate and instantaneous measurements in any environment.
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Hardware Overview
How does it work?
Magneto 14 Click is based on the MA735, a contactless angle sensor with ABZ and PWM output from Monolithic Power Systems. It can detect the absolute angular position of a permanent magnet, typically a diametrically magnetized cylinder on a rotating shaft. The adjustable digital filtering can optimize control loop performance when used in servo applications. In addition, the sensor features magnetic field strength detection with a programmable threshold and on-chip non-volatile memory. This memory can store configuration parameters, including magnetic field detection thresholds, ABZ encoder settings, and reference zero-angle positions. The frequency of the PWM output of the sensor is up to 1090Hz with a 14-bit resolution. The MA735 uses integrated Hall devices to detect the magnetic field, while the angle is measured using MPS’s proprietary Spinaxis™
method. This method is based on phase detection and digitizes the direction of the field directly, generating a sinusoidal signal with a phase that represents the angle of the field. The angle is obtained from a signal by a time-to-digital converter, and the digital number proportional to the magnetic field is delivered at a rate of 1MHz. Two headers on this Click board™ allow additional functionalities. The SSI header with SSD and SCK pins is a 2-wire synchronous serial interface for data reading only and can be used for angle reading operation. The INC OUT header is an incremental output encoder with A, B, and Z pins. The ABZ encoder emulates a 12-bit incremental encoder (like an optical encoder), providing logic pulses per turn from 1 to 1024 in quadrature. A unique addition to this board is a position for a Rotary Magnet Holder designed to be used alongside a magnetic contactless angle sensor,
allowing fast prototyping and quick measurements during development. The Magneto 14 Click uses a standard 4-Wire SPI serial interface with a maximum supported clock rate of 25MHz. The PWM absolute output provides a logic signal with a duty cycle proportional to the angle of the magnetic field on the pin PWM of the mikroBUS™ socket. This sensor has two thresholds, MGL and MGH, for low and high magnetic fields. The magnetic field high threshold (MFHT) is indicated over the MGH interrupt pin, together with an additional MGH red LED. 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
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.
Rotary Magnetic Holder is an addition designed for use alongside a magnetic rotary position sensor. It comes with a plastic stand measuring 22x16x10 millimeters (L x W x H), as well as an adjustable shaft with a 6mm diameter magnet. The plastic frame has four round feet that fit into holes in the board near the magnetic rotary position sensor, with a 6mm diameter hole on top to match the adjustable shaft that carries the magnet. This shaft has a height adjustment screw on it, allowing the user to adjust it between 18 and 22 millimeters. This way, fast prototyping and quick measurements of the magnet characteristics are allowed during development.
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 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 Magneto 14 Click driver.
Key functions:
magneto14_get_angle- Magneto 14 gets the angular position function.magneto14_get_field_strength- Magneto 14 gets the magnetic field strength function.magneto14_get_mgh- Magneto 14 gets the MGH 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 main.c
* @brief Magneto 14 Click example
*
* # Description
* This library contains API for the Magneto 14 Click driver.
* The demo application reads and displays
* the magnet's angular position in degrees.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization of SPI module and log UART.
* After driver initialization, the app executes a default configuration.
*
* ## Application Task
* This example demonstrates the use of the Magneto 14 Click board™.
* Reads and displays the magnet's angular position in degrees.
* Results are being sent to the UART Terminal, where you can track their changes.
*
* @author Nenad Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "magneto14.h"
static magneto14_t magneto14;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
magneto14_cfg_t magneto14_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.
magneto14_cfg_setup( &magneto14_cfg );
MAGNETO14_MAP_MIKROBUS( magneto14_cfg, MIKROBUS_1 );
if ( SPI_MASTER_ERROR == magneto14_init( &magneto14, &magneto14_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( MAGNETO14_ERROR == magneto14_default_cfg ( &magneto14 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
log_printf( &logger, " -------------------- \r\n" );
Delay_ms( 100 );
}
void application_task ( void )
{
static uint8_t field_strength = 0;
static float angle = 0;
if ( MAGNETO14_OK == magneto14_get_field_strength( &magneto14, &field_strength ) )
{
if ( ( MAGNETO14_FLD_ST_OK == field_strength ) &&
( MAGNETO14_MGH_ST_OK == magneto14_get_mgh( &magneto14 ) ) &&
( MAGNETO14_OK == magneto14_get_angle( &magneto14, &angle ) ) )
{
log_printf( &logger, " Angle: %.2f [deg]\r\n", angle );
log_printf( &logger, " -------------------- \r\n" );
Delay_ms( 1000 );
}
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
