Intermediate
30 min

Achieve fast data transfer with some Bluetooth magic thanks to the RN4678 and PIC24FV16KA304

Break free from cables

RN4678 Click with EasyPIC v8 for PIC24/dsPIC33

Published Nov 01, 2023

Click board™

RN4678 Click

Development board

EasyPIC v8 for PIC24/dsPIC33

Compiler

NECTO Studio

MCU

PIC24FV16KA304

Explore how this wireless method serves as a convenient alternative to cables, empowering users with effortless data exchange and intuitive device management for enhanced connectivity and productivity

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Hardware Overview

How does it work?

RN4678 Click is based on the RN4678, a Bluetooth® 4.2 dual-mode module from Microchip. This Click is designed to run on a 3.3V power supply. It communicates with the target microcontroller over I2C and UART interface, with additional functionality provided by the following pins on the mikroBUS™ line: AN, RST, CS, PWM, INT. The RN4678 from Microchip is a fully certified Bluetooth version 4.2 module. Use it to add Bluetooth wireless capability to your project.

The module includes an onboard Bluetooth stack, power management subsystem, 2.4 GHz transceiver, and RF power amplifier. Data transfer is achieved through Bluetooth by sending or receiving data through SPP in Bluetooth (BT) Classic mode and Transparent UART in BLE mode. The RN4678 contains an integral ceramic chip antenna. The RN4678 module has strong AES128 Encryption. 128-bit encryption is one of the most robust encryption algorithms. AES stands for

Advanced Encryption Standard, a symmetric encryption algorithm. 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.

RN4678 Click hardware overview image

Features overview

Development board

EasyPIC v8 for PIC24/dsPIC33 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit PIC24/dsPIC33 microcontrollers from Microchip and has a broad set of unique functions, such as the first-ever embedded debugger/programmer. 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, EasyPIC v8 for PIC24/dsPIC33 provides a fluid and immersive working experience, allowing access anywhere and under any circumstances. Each part of the EasyPIC

v8 for PIC24/dsPIC33 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 HOST/DEVICE, USB-UART, CAN, and LIN are also

included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 16-bit PIC24/dsPIC33 MCUs, from the smallest PIC24/dsPIC33 MCUs with only 14 up to 28 pins. EasyPIC v8 for PIC24/dsPIC33 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.

EasyPIC v8 for PIC24/dsPIC33 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Architecture

dsPIC

MCU Memory (KB)

16

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

Used MCU Pins

mikroBUS™ mapper

Software Button
RA0
AN
Module Reset
RB4
RST
UART RTS
RA4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Sleep Wake
RB13
PWM
UART CTS
RB7
INT
UART TX
RB0
TX
UART RX
RB1
RX
I2C Clock
RB6
SCL
I2C Data
RB5
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

RN4678 Click Schematic schematic

Step by step

Project assembly

EasyPIC v8 for PIC24/dsPIC33 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 for PIC24/dsPIC33 as your development board.

EasyPIC v8 for PIC24/dsPIC33 front image hardware assembly
Buck 22 Click front image hardware assembly
MCU DIP 28 hardware assembly
EasyPIC PIC24/dsPIC33 v8 DIP 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 DIP 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 RN4678 Click driver.

Key functions:

  • rn4678_enter_command_mode - Enter the command mode function

  • rn4678_exit_command_mode - Exit the command mode function

  • rn4678_set_device_name - Set the device name 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 RN4678 Click example
 * 
 * # Description
 * This example reads and processes data from RN4678 clicks.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes the driver and configures the click board.
 * 
 * ## Application Task  
 * Checks for the received data, reads it and replies with a certain message.
 * 
 * ## Additional Function
 * - rn4678_process ( ) - Logs all the received messages/responses on the USB UART, 
 *                        and if it receives "Hello" string it sends the certain message 
 *                        back to the connected device.
 * 
 * @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.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rn4678.h"
#include "string.h"

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

#define PROCESS_RSP_ERROR  -1
#define PROCESS_RSP_OK     1
#define PROCESS_NO_RSP     0
#define PROCESS_LOG_RSP    0

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

static rn4678_t rn4678;
static log_t logger;

uint8_t DEVICE_NAME_DATA[ 20 ] = { 'R', 'N', '4', '6', '7', '8', ' ', '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 rn4678_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;
    int8_t rsp_flag = 0;
    
    // Clear current buffer
    memset( current_parser_buf, 0, PROCESS_PARSER_BUFFER_SIZE ); 
    
    while( process_cnt != 0 )
    {
        rsp_size = rn4678_generic_read( &rn4678, 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 );
            
            if ( strstr( current_parser_buf, "ERR" ) ) {
                Delay_100ms( );
                rsp_flag = PROCESS_RSP_ERROR;
                break;
            }
            
            if ( PROCESS_LOG_RSP != response )
            {
                if ( strstr( current_parser_buf, response ) ) {
                    Delay_100ms( );
                    rsp_flag = PROCESS_RSP_OK;
                    break;
                }
            }
            else
            {
                rsp_flag = PROCESS_RSP_OK;
                process_cnt = 1;
            }
            
            if ( strstr( current_parser_buf, "Hello" ) ) {
                rn4678_generic_write( &rn4678, "MikroE\r\n", 8 );
                Delay_100ms( );
                break;
            }
        } 
        else 
        {
            process_cnt--;
            
            // Process delay 
            Delay_ms( 100 );
        }
    }
    
    if ( PROCESS_NO_RSP != rsp_flag )
    {
        log_printf( &logger, "%s", current_parser_buf );
        log_printf( &logger, "\r\n---------------------------\r\n" );
        return rsp_flag;
    }
    
    return PROCESS_NO_RSP;
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    rn4678_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.

    rn4678_cfg_setup( &cfg );
    RN4678_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rn4678_init( &rn4678, &cfg );

    rn4678_enable ( &rn4678 );
    Delay_ms( 1000 );
    rn4678_hw_reset ( &rn4678 );
    Delay_ms( 1000 );
    
    log_printf( &logger, "Configuring the module...\n" );
    
    do
    {    
        log_printf( &logger, " --- Command mode --- \r\n" );
        rn4678_enter_command_mode( &rn4678 );
    }
    while( rn4678_process( "CMD" ) != 1 );
    
    do
    {
        log_printf( &logger, " --- Device name --- \r\n" );
        rn4678_set_device_name( &rn4678, &DEVICE_NAME_DATA[ 0 ] );
    }
    while( rn4678_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Status string --- \r\n" );
        rn4678_set_extended_status_string( &rn4678, &EXTENDED_STRING_DATA[ 0 ] );
    }
    while( rn4678_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Operating mode --- \r\n" );
        rn4678_set_operating_mode( &rn4678, 0 );
    }
    while( rn4678_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Authentication --- \r\n" );
        rn4678_set_authentication( &rn4678, 1 );
    }
    while( rn4678_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Pin code --- \r\n" );
        rn4678_set_security_pin_code( &rn4678, &PIN_CODE_DATA[ 0 ] );
    }
    while( rn4678_process( "AOK" ) != 1 );

    do
    {
        log_printf( &logger, " --- Exit command mode --- \r\n" );
        rn4678_exit_command_mode( &rn4678 );
    }
    while( rn4678_process( "END" ) != 1 );
    
    log_printf( &logger, "The module has been configured.\n" );
    
    rn4678_set_cts_pin( &rn4678, 0 );
}

void application_task ( void )
{
    rn4678_process( PROCESS_LOG_RSP );
}

void main ( void )
{
    application_init( );

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


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

Additional Support

Resources