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Incorporate high-quality Bluetooth audio streaming into your projects with BM62 and PIC18F57Q43

Fully qualified Bluetooth 5.0 stereo audio module

BT Audio 2 Click with Curiosity Nano with PIC18F57Q43

Published Mar 15, 2024

Click board™

BT Audio 2 Click

Dev Board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Create the next generation of portable audio devices and voice communication systems

A

A

Hardware Overview

How does it work?

BT Audio 2 Click is based on BM62, a Bluetooth stereo audio module from Microchip. It includes advanced audio features, such as multi-band dynamic range control, parametric multi-band equalizer, audio widening, and virtual bass are inbuilt. The audio effect algorithms improve the user’s audio listening experience in terms of better audio quality after audio signal processing. The input and output audios have different stages, and each stage can be programmed to vary the gain response characteristics. A Digital Signal Processor (DSP) performs speech and audio processing. Advanced speech features, such as acoustic echo cancellation and noise reduction, are built. To

reduce nonlinear distortion and to help echo cancellation, an outgoing signal level to the speaker is monitored and adjusted to avoid saturation of speaker output or microphone input. BT Audio 2 Click supports one analog (line-in) signal from the external audio source. The DSP can process the analog (line-in) signal to generate different sound effects (multi-band dynamic range compression and audio widening), which can be configured using the DSP tool. Also, the module has an AFH function to avoid RF interference. It has an algorithm to check the nearby interference and to choose a clear channel for the transceiver Bluetooth signal. The on-chip Power Management

Unit (PMU) has two main features: a lithium-ion and lithium-polymer battery charger and a voltage regulator. A power switch switches the power source between the battery and an adapter. Also, the PMU provides current to drive two LEDs. The LED and button settings can be configured. This Click Board™ uses the UART communication interface and is designed to be operated only with a 3.3V logic level. A proper logic voltage level conversion should be performed before the Click board™ is used with MCUs with different logic levels.

BT Audio 2 Click hardware overview image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

These standard small stereo earphones offer a high-quality listening experience with their top-notch stereo cable and connector. Designed for universal compatibility, they effortlessly connect to all MIKROE mikromedia and multimedia boards, making them an ideal choice for your electronic projects. With a rated power of 100mW, the earphones provide crisp audio across a broad frequency range from 20Hz to 20kHz. They boast a sensitivity of 100 ± 5dB and an impedance of 32Ω ± 15%, ensuring optimal sound quality. The Φ15mm speaker delivers clear and immersive audio. Cost-effective and versatile, these earphones are perfect for testing your prototype devices, offering an affordable and reliable audio solution to complement your projects.

BT Audio 2 Click accessories 1 image

Used MCU Pins

mikroBUS™ mapper

External Address Bus Negative
PA0
AN
Reset
PA7
RST
System Configuration PIn 1
PD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
NC
NC
3.3V
Ground
GND
GND
Multifunction button / Power-On
PB0
PWM
System Configuration PIn 2
PA6
INT
UART TX
PC2
TX
UART RX
PC3
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

BT Audio 2 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PICXXX 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 image step 5 hardware assembly
Necto image step 6 hardware assembly
PIC18F57Q43 Curiosity MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 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.

Application Output Step 1

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™.

Application Output Step 3

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.

Application Output Step 4

Software Support

Library Description

This library contains API for BT Audio 2 Click driver.

Key functions:

  • btaudio2_set_device_name - This function sets the local device name

  • btaudio2_make_call - This function makes a call to the specified phone number

  • btaudio2_volume_up - This function increases the volume of a specified gain mask

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 BT Audio 2 Click Example.
 *
 * # Description
 * This example demonstrates the use of BT Audio 2 click board by reading the commands
 * received from remote device and performing adequate actions accordingly.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and configures the click board.
 *
 * ## Application Task
 * Reads all the received events and parses them.
 *
 * ## Additional Function
 * - static err_t btaudio2_event_handler ( btaudio2_t *ctx ) - This function handles SPP data event 
 * and several BTM state events added in. The other events will just be displayed on the USB UART in hex format.
 *
 * @note
 * We have used the Serial Bluetooth Terminal smartphone application for the test. 
 * A smartphone and the click board must be paired in order to exchange messages
 * with each other. So make sure to pair your device with the click board and
 * connect it to using the Serial Bluetooth Terminal application, then you will be able 
 * to send commands listed below.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "btaudio2.h"

static btaudio2_t btaudio2;
static log_t logger;

// Bluetooth device name
#define DEVICE_NAME                 "BT Audio 2 click"

// SPP Commands list
#define COMMAND_PLAY                "play"          // play music
#define COMMAND_PAUSE               "pause"         // pause music
#define COMMAND_STOP                "stop"          // stop music
#define COMMAND_NEXT                "next"          // next song
#define COMMAND_PREVIOUS            "prev"          // previous song
#define COMMAND_VOLUME_UP           "up"            // volume up
#define COMMAND_VOLUME_DOWN         "down"          // volume down
#define COMMAND_MODE_UP             "mode"          // switch equalizer mode
#define COMMAND_CALL                "call"          // call command followed by the number
#define COMMAND_VOICE               "voice"         // start voice recognition app

/**
 * @brief BT Audio 2 event handler function.
 * @details This function handles SPP data event and several BTM state events added in.
 * The other events will just be displayed on the USB UART in hex format.
 * @param[in] ctx : Click context object.
 * See #btaudio2_t object definition for detailed explanation.
 * @return @li @c  >=0 - Command ACK event response,
 *         @li @c   -1 - Error.
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t btaudio2_event_handler ( btaudio2_t *ctx );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    btaudio2_cfg_t btaudio2_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.
    btaudio2_cfg_setup( &btaudio2_cfg );
    BTAUDIO2_MAP_MIKROBUS( btaudio2_cfg, MIKROBUS_1 );
    if ( UART_ERROR == btaudio2_init( &btaudio2, &btaudio2_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( BTAUDIO2_OK != btaudio2_default_cfg ( &btaudio2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    if ( BTAUDIO2_OK != btaudio2_set_device_name ( &btaudio2, DEVICE_NAME ) )
    {
        log_error( &logger, " Set device name." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    if ( BTAUDIO2_OK == btaudio2_read_event ( &btaudio2 ) ) 
    {
        btaudio2_event_handler ( &btaudio2 );
    }
}

int main ( void ) 
{
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

static err_t btaudio2_event_handler ( btaudio2_t *ctx )
{
    err_t error_flag = BTAUDIO2_OK;
    static btaudio2_eq_mode_t eq_mode = BTAUDIO2_EQ_MODE_OFF;
    switch ( ctx->event_packet.opcode )
    {
        case BTAUDIO2_EVT_REPORT_SPP_DATA:
        {
            if ( 0 == ctx->event_packet.param_buf[ 1 ] ) // single packet
            {                
                uint16_t payload_len = ( ( uint16_t ) ctx->event_packet.param_buf[ 4 ] << 8 ) | 
                                                      ctx->event_packet.param_buf[ 5 ];
                if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_PLAY ) )
                {
                    error_flag |= btaudio2_send_mmi_action ( ctx, 0, BTAUDIO2_MMI_PLAY_PAUSE_MUSIC );
                    log_printf( &logger, " > play music\r\n\n" );
                } 
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_PAUSE ) )
                {
                    error_flag |= btaudio2_send_mmi_action ( ctx, 0, BTAUDIO2_MMI_PLAY_PAUSE_MUSIC );
                    log_printf( &logger, " > pause music\r\n\n" );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_STOP ) )
                {
                    error_flag |= btaudio2_send_mmi_action ( ctx, 0, BTAUDIO2_MMI_STOP_MUSIC );
                    log_printf( &logger, " > stop music\r\n\n" );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_NEXT ) )
                {
                    error_flag |= btaudio2_send_mmi_action ( ctx, 0, BTAUDIO2_MMI_NEXT_SONG );
                    log_printf( &logger, " > next song\r\n\n" );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_PREVIOUS ) )
                {
                    error_flag |= btaudio2_send_mmi_action ( ctx, 0, BTAUDIO2_MMI_PREVIOUS_SONG );
                    log_printf( &logger, " > previous song\r\n\n" );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_VOLUME_UP ) )
                {
                    error_flag |= btaudio2_volume_up ( &btaudio2, 0, BTAUDIO2_VOLUME_MASK_A2DP );
                    log_printf( &logger, " > volume up\r\n\n" );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_VOLUME_DOWN ) )
                {
                    error_flag |= btaudio2_volume_down ( &btaudio2, 0, BTAUDIO2_VOLUME_MASK_A2DP );
                    log_printf( &logger, " > volume down\r\n\n" );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_CALL ) )
                {
                    uint8_t phone_number[ 19 ] = { 0 };
                    memcpy ( phone_number, strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_CALL ) + 5, payload_len - 7 );
                    error_flag |= btaudio2_make_call ( &btaudio2, 0x00, phone_number );
                    log_printf( &logger, " > calling number: %s\r\n\n", phone_number );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_VOICE ) )
                {
                    error_flag |= btaudio2_send_mmi_action ( ctx, 0, BTAUDIO2_MMI_VOICE_DIAL );
                    log_printf( &logger, " > start voice recognition\r\n\n" );
                }
                else if ( strstr ( &ctx->event_packet.param_buf[ 6 ], COMMAND_MODE_UP ) )
                {
                    if ( BTAUDIO2_EQ_MODE_USER1 == eq_mode )
                    {
                        eq_mode = BTAUDIO2_EQ_MODE_OFF;
                    }
                    else
                    {
                        eq_mode++;
                    }
                    btaudio2_set_eq_mode ( &btaudio2, eq_mode );
                    log_printf( &logger, " > equalizer mode: " );
                    switch ( eq_mode )
                    {
                        case BTAUDIO2_EQ_MODE_OFF:
                        {
                            log_printf( &logger, "off\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_SOFT:
                        {
                            log_printf( &logger, "soft\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_BASS:
                        {
                            log_printf( &logger, "bass\r\n\n" );
                            break;
                        } 
                        case BTAUDIO2_EQ_MODE_TREBLE:
                        {
                            log_printf( &logger, "treble\r\n\n" );
                            break;
                        }  
                        case BTAUDIO2_EQ_MODE_CLASSIC:
                        {
                            log_printf( &logger, "classic\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_ROCK:
                        {
                            log_printf( &logger, "rock\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_JAZZ:
                        {
                            log_printf( &logger, "jazz\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_POP:
                        {
                            log_printf( &logger, "pop\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_DANCE:
                        {
                            log_printf( &logger, "dance\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_RNB:
                        {
                            log_printf( &logger, "rnb\r\n\n" );
                            break;
                        }
                        case BTAUDIO2_EQ_MODE_USER1:
                        {
                            log_printf( &logger, "user1\r\n\n" );
                            break;
                        }
                        default:
                        {
                            log_printf( &logger, "unknown\r\n\n" );
                            break;
                        }
                    }
                }
                else
                {
                    log_printf( &logger, " Unknown command: ", &ctx->event_packet.param_buf[ 6 ] );
                    for ( uint16_t cnt = 0; cnt < payload_len; cnt++ )
                    {
                        log_printf( &logger, "%c", ctx->event_packet.param_buf[ cnt + 6 ] );
                    }
                    log_printf( &logger, "\r\n\n" );
                }
            }
            break;
        }
        case BTAUDIO2_EVT_BTM_STATE:
        {
            switch ( ctx->event_packet.param_buf[ 0 ] )
            {
                case BTAUDIO2_BTM_STATE_PAIRING_SUCCESSFULL:
                {
                    log_printf( &logger, " < Pairing successfull - linked device ID: %u\r\n\n", 
                                ( uint16_t ) ctx->event_packet.param_buf[ 1 ] );
                    break;
                }
                case BTAUDIO2_BTM_STATE_SCO_LINK_CONNECTED:
                {
                    log_printf( &logger, " < SCO link connected - linked device ID: %u\r\n\n", 
                                ( uint16_t ) ctx->event_packet.param_buf[ 1 ] );
                    break;
                }
                case BTAUDIO2_BTM_STATE_SCO_LINK_DISCONNECTED:
                {
                    log_printf( &logger, " < SCO link disconnected - linked device ID: %u\r\n\n", 
                                ( uint16_t ) ctx->event_packet.param_buf[ 1 ] );
                    break;
                }
                case BTAUDIO2_BTM_STATE_ACL_CONNECTED:
                {
                    log_printf( &logger, " < ACL connected - linked data base: %u\r\n\n", 
                                ( uint16_t ) ctx->event_packet.param_buf[ 1 ] );
                    break;
                }
                case BTAUDIO2_BTM_STATE_ACL_DISCONNECTED:
                {
                    log_printf( &logger, " < ACL disconnected - " );
                    if ( 0 == ctx->event_packet.param_buf[ 1 ] )
                    {
                        log_printf( &logger, "disconnection\r\n\n" );
                    }
                    else if ( 1 == ctx->event_packet.param_buf[ 1 ] )
                    {
                        log_printf( &logger, "link loss\r\n\n" );
                    }
                    break;
                }
                case BTAUDIO2_BTM_STATE_STANDBY_STATE:
                {
                    log_printf( &logger, " < Standby state\r\n\n" );
                    break;
                }
                case BTAUDIO2_BTM_STATE_UNKNOWN_AUDIO_SOURCE:
                {
                    log_printf( &logger, " < Unknown audio source\r\n\n" );
                    break;
                }
                case BTAUDIO2_BTM_STATE_AUX_IN_AUDIO_SOURCE:
                {
                    log_printf( &logger, " < AUX-IN audio source\r\n\n" );
                    break;
                }
                case BTAUDIO2_BTM_STATE_A2DP_AUDIO_SOURCE:
                {
                    log_printf( &logger, " < A2DP audio source\r\n\n" );
                    break;
                }
                default:
                {
                    log_printf( &logger, " < EVENT BTM STATE: " );
                    for ( uint16_t cnt = 0; cnt < ctx->event_packet.param_len; cnt++ )
                    {
                        log_printf( &logger, "0x%.2X ", ( uint16_t ) ctx->event_packet.param_buf[ cnt ] );
                    }
                    log_printf( &logger, "\r\n\n" );
                    break;
                }
            }
            break;
        }
        default: 
        {
            log_printf( &logger, " < EVENT 0x%.2X: ", ( uint16_t ) ctx->event_packet.opcode );
            for ( uint16_t cnt = 0; cnt < ctx->event_packet.param_len; cnt++ )
            {
                log_printf( &logger, "0x%.2X ", ( uint16_t ) ctx->event_packet.param_buf[ cnt ] );
            }
            log_printf( &logger, "\r\n\n" );
            break;
        }
    }
    return error_flag;
}

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

Additional Support

Resources