Beginner
10 min

Provide Bluetooth connectivity for any embedded application with RN-41 and PIC32MZ2048EFM100

Connect and share data without the need for physical cables

Bluetooth Click with Curiosity PIC32 MZ EF

Published Nov 03, 2023

Click board™

Bluetooth Click

Dev. board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

Add Bluetooth connectivity into your embedded projects with extended range, compatibility with Bluetooth version 2.1 + EDR, and resilience in high-interference environments

A

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Hardware Overview

How does it work?

Bluetooth Click is based on the RN-41, a Class 1 Bluetooth module from Microchip. The auto-discovery/pairing on this module does not require software configuration. It has a 15dBm output transmitter with -80dBm of typical receive sensitivity for transmitting data using FHSS/GFSK modulation on 79 channels and at 1MHz intervals. The 3Mbps data rate communication is secured with 128-bit encryption, with error correction, which guarantees packet delivery. The 3Mbps data rate is a maximum that can be achieved in a burst in HCI mode, while the 1.5Mbps is sustained. To communicate with the host MCU, the Bluetooth Click uses the UART interface with commonly used

UART RX and TX as its default communication protocol. It can operate at baud rate speeds from 1200bps to 921Kbps, while non-standard baud rates can be programmed. The hardware flow control pins UART CTS/RTS are disabled and can be enabled by soldering J1 and J2 jumpers. The RN-41 module can be programmed over the UART interface of the mikroBUS™ socket with a simple ASCI command language similar to the Hayes AT protocol. The module can be reset via the RST pin with active LOW. This Click board™ features four more jumpers labeled PIO3, PIO4, PIO6, and PIO7. The auto-discovery function can be enabled by soldering jumper PIO3. To set the factory default

values, you should solder the PIO4 jumper, and this feature is critical when the module has been misconfigured. The auto-master mode can be set by soldering the PIO6 jumper; the standard application runs on SPP/DUN Master and Slave. The firmware can set the baud rate but can also be forced to 9600bps by soldering the PIO7 jumper. 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.

Bluetooth  Click hardware overview image

Features overview

Development board

Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand

functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,

which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.

Curiosity PIC32MZ EF double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RA9
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
UART TX
RPD10
TX
UART RX
RPD15
RX
UART RTS
RPA14
SCL
UART CTS
RPA15
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Bluetooth Click Schematic schematic

Step by step

Project assembly

Curiosity PIC32MZ EF front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.

Curiosity PIC32MZ EF front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Curiosity PIC32 MZ EF MB 1 Access - 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
Curiosity PIC32 MZ EF 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

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 Bluetooth Click driver.

Key functions:

  • bluetooth_enter_command_mode - The function enter the command mode of the RN-41 Bluetooth module on Bluetooth Click board.

  • bluetooth_set_authentication - The function set the authentication value to the RN-41 Bluetooth module on Bluetooth Click board.

  • bluetooth_set_security_pin_code - The function set security pin code string to the RN-41 Bluetooth module on Bluetooth Click board.

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 
 * \brief Bluetooth Click example
 * 
 * # Description
 * This example reads and processes data from Bluetooth clicks.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver and wake-up module.
 * 
 * ## Application Task  
 * Reads the received data.
 * 
 * ## Additional Function
 * - bluetooth_process ( ) - Logs all received messages on UART, and sends the certain message back to the connected device.
 * 
 * *note:* 
 * Before starting to use this click, it must be paired with other device.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "bluetooth.h"
#include "string.h"

#define PROCESS_COUNTER 20
#define PROCESS_RX_BUFFER_SIZE 100
#define PROCESS_PARSER_BUFFER_SIZE 100

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

static bluetooth_t bluetooth;
static log_t logger;

uint8_t DEVICE_NAME_DATA[ 20 ] = { 'B', 'l', 'u', 'e', 't', 'o', 'o', 't', 'h', 'C', 'l', 'i', 'c', 'k' };
uint8_t EXTENDED_STRING_DATA[ 10 ] = { 'S', 'l', 'a', 'v', 'e' };
uint8_t PIN_CODE_DATA[ 10 ] = { '1', '2', '3', '4' };
static char current_parser_buf[ PROCESS_PARSER_BUFFER_SIZE ];

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

static int8_t bluetooth_process ( char * response )
{
    int32_t rsp_size;
    uint16_t rsp_cnt = 0;
    
    char uart_rx_buffer[ PROCESS_RX_BUFFER_SIZE ] = { 0 };
    uint8_t check_buf_cnt;
    uint8_t process_cnt = PROCESS_COUNTER;
    
    // Clear current buffer
    memset( current_parser_buf, 0, PROCESS_PARSER_BUFFER_SIZE ); 
    
    while( process_cnt != 0 )
    {
        rsp_size = bluetooth_generic_read( &bluetooth, uart_rx_buffer, PROCESS_RX_BUFFER_SIZE );

        if ( rsp_size > 0 )
        {  
            // Validation of the received data
            for ( check_buf_cnt = 0; check_buf_cnt < rsp_size; check_buf_cnt++ )
            {
                if ( uart_rx_buffer[ check_buf_cnt ] == 0 ) 
                {
                    uart_rx_buffer[ check_buf_cnt ] = 13;
                }
            }
            // Storages data in current buffer
            rsp_cnt += rsp_size;
            if ( rsp_cnt < PROCESS_PARSER_BUFFER_SIZE )
            {
                strncat( current_parser_buf, uart_rx_buffer, rsp_size );
            }
            
            // Clear RX buffer
            memset( uart_rx_buffer, 0, PROCESS_RX_BUFFER_SIZE );
            
            log_printf( &logger, "%s", current_parser_buf );
            
            if ( strstr( current_parser_buf, "ERR" ) ) {
               Delay_100ms( );
               return -1;
            }
            
            if ( strstr( current_parser_buf, response ) ) {
               Delay_100ms( );
               return 1;
            }
               
            if ( strstr( current_parser_buf, "Hello" ) ) {
                bluetooth_generic_write( &bluetooth, "MikroE\r\n", 8 );
                Delay_100ms( );
            }
        } 
        else 
        {
            process_cnt--;
            
            // Process delay 
            Delay_ms( 100 );
        }
    }
    
    return 0;
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    bluetooth_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.

    bluetooth_cfg_setup( &cfg );
    BLUETOOTH_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    bluetooth_init( &bluetooth, &cfg );

    Delay_ms( 500 );
   
    log_printf( &logger, "Configuring the module...\n" );
    
    do
    {    
        log_printf( &logger, " --- Command mode --- \r\n" );
        bluetooth_enter_command_mode( &bluetooth );
    }
    while( bluetooth_process( "CMD" ) != 1 );
    
    do
    {
        log_printf( &logger, " --- Device name --- \r\n" );
        bluetooth_set_device_name( &bluetooth, &DEVICE_NAME_DATA[ 0 ] );
    }
    while( bluetooth_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Status string --- \r\n" );
        bluetooth_set_extended_status_string( &bluetooth, &EXTENDED_STRING_DATA[ 0 ] );
    }
    while( bluetooth_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Operating mode --- \r\n" );
        bluetooth_set_operating_mode( &bluetooth, 0 );
    }
    while( bluetooth_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Authentication --- \r\n" );
        bluetooth_set_authentication( &bluetooth, 1 );
    }
    while( bluetooth_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Pin code --- \r\n" );
        bluetooth_set_security_pin_code( &bluetooth, &PIN_CODE_DATA[ 0 ] );
    }
    while( bluetooth_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Exit command mode --- \r\n" );
        bluetooth_exit_command_mode( &bluetooth );
    }
    while( bluetooth_process( "END" ) != 1 );
    
    log_printf( &logger, "The module has been configured.\n" );
}

void application_task ( void )
{
    bluetooth_process( "AOK" );
}

void main ( void )
{
    application_init( );

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


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

Additional Support

Resources

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