Measure the angle of a rotating shaft with ADA4570 and PIC32MX764F128L
The angle whisperer
Published Apr 06, 2023
Click board™
AMR Angle 2 Click
Dev. board
UNI Clicker
Compiler
NECTO Studio
MCU
PIC32MX764F128L
Experience precise and reliable angular position measurement of the surrounding magnetic field with an AMR angle sensor
A
A
Hardware Overview
How does it work?
AMR Angle 2 Click is based on the ADA4570, an anisotropic magnetoresistive (AMR) sensor with integrated signal conditioning amplifiers and analog-to-digital converter (ADC) drivers from Analog Devices. It consists of two dies within one package, an AMR sensor, and a fixed gain instrumentation amplifier producing two differential analog outputs that indicate the angular position of the surrounding magnetic field. These amplified differential cosine and sine output signals are delivered with respect to the angle when the magnetic field is rotating in the x-axis and the y-axis (x-y) plane. The ADA4570 contains two Wheatstone bridges at a relative angle of 45° to one another. A complete rotation of a dipole magnet produces two periods on the sinusoidal outputs, so the magnetic angle calculated from the sine and cosine
differential outputs represents the physical orientation of the magnet with respect to the ADA4570 in the 0° to 180° measurement range. Within a homogeneous field in the x-y plane, the output signals of the ADA4570 are independent of the physical placement in the z-direction (air gap). As mentioned before, alongside the AMR sensor, this Click board™ also contains one high-speed, low-power, serial output successive approximation register (SAR) analog-to-digital converter (ADC), the MAX11122 from Analog Devices. It processes sine and cosine outputs and then forwards them to the MCU via the SPI interface for further processing. Apart from the SPI communication lines, this Click board™ uses several more pins on the mikroBUS™ such as CST and EOC, routed to the PWM and INT pins of the mikroBUS™ socket,
representing the signals with which the AD conversion starts and the signal indicating the completion of the conversion itself, respectively. Also, the ADA4570 has an integrated temperature sensor that provides a voltage ratiometric to the ADA4570 supply voltage at the AN pin of the mikroBUS™ socket used to monitor the system's operating temperature and provide the reference for further calibration. This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ 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 Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build
gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li
Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker 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
Type
8th Generation
Architecture
PIC32
MCU Memory (KB)
128
Silicon Vendor
Microchip
Pin count
100
RAM (Bytes)
32768
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 UNI Clicker 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 AMR Angle 2 Click driver.
Key functions:
amrangle2_read_angleThis function reads Vsin and Vcos voltages and converts them to angle in Degrees.amrangle2_read_temperatureThis function reads temperature measurements in Celsius.amrangle2_read_vsin_vcosThis function reads a voltage of sine and cosine differential signal outputs.
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 main.c
* @brief AMR Angle 2 Click example
*
* # Description
* This example demonstrates the use of AMR Angle 2 click board by reading and displaying
* the magnet's angular position in Degrees and a system temperature in Celsius.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration.
*
* ## Application Task
* Reads the magnet's angular position in degrees and a system temperature in Celsius
* and displays the results on the USB UART approximately every 100ms.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "amrangle2.h"
static amrangle2_t amrangle2;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
amrangle2_cfg_t amrangle2_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.
amrangle2_cfg_setup( &amrangle2_cfg );
AMRANGLE2_MAP_MIKROBUS( amrangle2_cfg, MIKROBUS_1 );
if ( SPI_MASTER_ERROR == amrangle2_init( &amrangle2, &amrangle2_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( AMRANGLE2_ERROR == amrangle2_default_cfg ( &amrangle2 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
float angle, temperature;
if ( AMRANGLE2_OK == amrangle2_read_angle ( &amrangle2, &angle ) )
{
log_printf( &logger, " Angle: %.2f Degrees\r\n", angle );
}
if ( AMRANGLE2_OK == amrangle2_read_temperature ( &amrangle2, &temperature ) )
{
log_printf( &logger, " Temperature: %.2f C\r\n\n", temperature );
}
Delay_ms( 100 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
