Beginner
10 min

Provide Bluetooth connectivity for any embedded application with RN-41 and PIC32MX675F512L

Connect and share data without the need for physical cables

Bluetooth Click with Fusion for PIC32 v8

Published Nov 03, 2023

Click board™

Bluetooth Click

Dev.Board

Fusion for PIC32 v8

Compiler

NECTO Studio

MCU

PIC32MX675F512L

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

A

A

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

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)

512

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

65536

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PB0
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
PF13
TX
UART RX
PF12
RX
UART RTS
PA2
SCL
UART CTS
PA3
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

Bluetooth 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 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

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \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