Achieve exceptional accuracy in angle detection with A1335 and PIC18LF26K42

Magnet whisperer

Published Jan 23, 2024

Click board™

Angle Click

Dev Board

Curiosity HPC

Compiler

NECTO Studio

MCU

PIC18LF26K42

Harness the power of Hall effect technology to achieve accurate magnet angle sensing for your projects, enabling advanced control and measurement capabilities in a wide range of applications

Hardware Overview

How does it work?

Angle Click is based on the A1335, a precision Hall-effect angle sensor from Allegro Microsystems. It features a Circular Vertical Hall (CVH) technology, a high-speed sampling AD converter, a 32-bit MCU for data processing, EEPROM, and the section used for the I2C/SPI communication. The CVH sensor detects the rotation of the magnetic field by utilizing the effect the magnetic field produces on the electron flow within the sensor while the current flows through it. The signal from the sensor is then digitized by the AD converter and

handed to the digital front end of the IC. The digitalized signal is preconditioned and processed through the bandpass filter, and the raw value of the angle is calculated. The value is then forwarded to the MCU unit. It is submitted to various processing steps, depending on the register values set by the user. Angle Click can communicate with the host MCU using the SPI serial or I2C interfaces. The selection can be made over five COMM SEL jumpers. The I2C, which can support a clock frequency of up to 400kHz, is

selected by default. Over the ADDR SEL jumpers, you can set the I2C address (0s set by default). If your choice is the SPI, then you can count on 10MHz of clock frequency. This Click board™ can operate with either 3.3V or 5V logic voltage levels. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this 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

Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All

these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware

quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

4096

Used MCU Pins

mikroBUS™ mapper

RST

SPI Chip Select

RA3

SPI Clock

RB1

SCK

SPI Data OUT

RB2

MISO

SPI Data IN

RB3

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

RC3

SCL

I2C Data

RC4

SDA

Power Supply

Ground

GND

Take a closer look

Schematic

Step by step

Project assembly

Curiosity HPC front no-mcu image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity HPC as your development board.

IR Sense 4 Click front image hardware assembly

Curiosity HPC 28pin-DIP - upright/background hardware assembly

Necto DIP image step 7 hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step hardware assembly

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 Angle Click driver.

Key functions:

angle_get_angle - This function reads angle value
angle_get_temperature - This function reads temperature value
angle_get_magnetics - This function reads magnetics value.

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 Angle Click example
 * 
 * # Description
 * Angle click is a precise Hall-effect angle sensing click board that can be used to measure the rotational angle 
 * of the magnetic field in the X-Y plane above it (parallel to the surface of the click), through the whole range of 360°.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Driver intialization and Angle settings mode.
 * 
 * ## System Initialization  
 * Intializes I2C module.
 * 
 * ## Application Task  
 * Reads encoded Angle in degreeses and Magnetic data in gauss.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "angle.h"

// ------------------------------------------------------------------ VARIABLES

static angle_t angle;
static log_t logger;

uint16_t angle_val;
uint16_t magnetics_val;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    angle_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_info( &logger, "---- Application Init ----" );

    //  Click initialization.

    angle_cfg_setup( &cfg );
    ANGLE_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    angle_init( &angle, &cfg );
    angle_default_cfg ( &angle );
}

void application_task ( void )
{
    angle_val = angle_get_angle( &angle );
    log_printf( &logger, "Angle :%d \r\n", angle_val );
    
    magnetics_val = angle_get_magnetics( &angle );
    log_printf( &logger, "Magnetics :%d \r\n", magnetics_val );
    
    Delay_ms( 1000 );
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}


// ------------------------------------------------------------------------ END