Intermediate
30 min

Elevate your audio experience with MCP6H012 and PIC32MZ2048EFH144

The audiophile's dream: Analog active crossovers redefining sound purity

Audio Xover Click with Fusion for PIC32 v8

Published Oct 22, 2023

Click board™

Audio Xover Click

Dev Board

Fusion for PIC32 v8

Compiler

NECTO Studio

MCU

PIC32MZ2048EFH144

Delve into the realm of high-fidelity audio with our analog active crossover solution, designed to enhance clarity and precision in two-way loudspeakers

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Hardware Overview

How does it work?

Audio Xover Click is based on the MCP6H012, an operational amplifier with rail-to-rail output operation from Microchip. It uses three Butterworth filters (one for each speaker) with possibility of changing cutoff frequency between 120Hz, 90Hz and 70Hz. Butterworth filters are called maximally flat filters because, for a given order, they have the sharpest roll-off possible without inducing peaking in the Bode plot. The two-pole filter with a damping ratio of 0.707 is the second-order Butterworth filter. Audio crossovers are a type of electronic filter circuitry used in a range of audio applications, to split up an audio signal into two or more frequency ranges, so that

the signals can be sent to drivers that are designed for different frequency ranges. Active crossovers are distinguished from passive crossovers in that whereas passive crossovers split up an amplified signal coming from one power amplifier so that it can be sent to two or more drivers (e.g., a woofer and a very low frequency subwoofer, or a woofer and a tweeter), an active crossover splits up audio signal prior to amplification, so that it can be sent to two or more power amplifiers, each of which is connected to a separate driver type. Active crossovers as Audio Xover Click don’t care how powerful your amplifiers are because they process the signal

before it enters the amplifier. Active crossovers are also not very sensitive to temperature variations, so they can be very accurate, all the time. If one of the amplifiers channels in an active crossover system clips, the distortion only affects that single channel. This Click board™ can be operated only with a 5V 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.

Audio Xover Click hardware overview image

Features overview

Development board

Fusion for PIC32 v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of Microchip's PIC32 microcontrollers 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, Fusion for PIC32 v8 provides a fluid and immersive working experience, allowing access anywhere and under any circumstances at any time. Each part of the

Fusion for PIC32 v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board 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. Fusion for PIC32 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.

Fusion for PIC32 v8 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

144

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
Shutdown
PH3
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
NC
NC
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

Audio Xover Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for PIC32 v8 as your development board.

Fusion for PIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

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.

UART Application Output Step 1

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.

UART Application Output Step 2

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".

UART Application Output Step 3

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.

UART Application Output Step 4

Software Support

Library Description

This library contains API for Audio Xover Click driver.

Key functions:

  • audioxover_power_on - Device power on function.

  • audioxover_shut_down - Device shut down 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 
 * \brief Audio Xover Click example
 * 
 * # Description
 * This example demonstrates the use of the Audio Xover click board. 
 * The click is an analog active crossover solution for two-way loudspeakers. 
 * The primary purpose of the crossover circuit in a loudspeaker is to split 
 * an incoming audio signal into frequency bands that are passed to 
 * the speaker best suited.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * This function initializes the driver and makes an initial log.
 * 
 * ## Application Task  
 * This function enables and disables the click board every 10 seconds,
 * and logs an appropriate message on the USB UART.
 * 
 * @note
 * The hardware revision v100 of the click board works only with MCUs that operates
 * at 5V operating voltage level.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "audioxover.h"

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

static audioxover_t audioxover;
static log_t logger;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    audioxover_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.

    audioxover_cfg_setup( &cfg );
    AUDIOXOVER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    audioxover_init( &audioxover, &cfg );
}

void application_task ( void )
{
    log_printf( &logger, " * Switch: ON *\r\n" );
    audioxover_power_on ( &audioxover );
    Delay_ms( 10000 );

    log_printf( &logger, " * Switch: OFF *\r\n" );
    audioxover_shut_down ( &audioxover );
    Delay_ms( 10000 );
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources

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