Intermediate
30 min

Embrace the future of communication with BM832A and ATmega644P

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BLE 12 Click with EasyAVR v7

Published Jul 29, 2023

Click board™

BLE 12 Click

Dev Board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega644P

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Hardware Overview

How does it work?

BLE 12 Click is based on the BM832A, a highly flexible, ultra-low power Bluetooth module that provides BLE connectivity for any embedded application from Fanstel. The BM832A module is based on the Nordic nRF52 SoC, which integrates a 64MHz, 32bit ARM Cortex M4 processor with a floating-point unit (FPU) and a 2.4GHz multiprotocol radio (supporting Bluetooth 5.0 and an integrated PCB trace antenna), featuring -96dBm RX sensitivity (depending on data rate), alongside 192kB Flash memory and 24kB RAM. BLE 12 Click allows UART and SPI interfaces, with commonly used UART RX and TX pins as its default communication protocol for exchanging AT commands operating at 115200 bps by default configuration, to transmit and exchange data with the host MCU. The selection can be made by positioning SMD jumpers labeled COMM SEL in an appropriate position. Note that all the jumpers' positions must be on the same side, or the Click

board™ may become unresponsive. The CMD pin routed on the PWM pin of the mikroBUS™ represents the communication-activation feature. A high logic state of the CMD pin allows the module to communicate with the MCU, while a low state allows data to be sent to a far-end device (for example, a smartphone) transparently. With the selected UART interface, power consumption can be reduced by sending the command "AT+STOP". The CS pin must be set to a low logic state for 200μs or more to wake up the UART interface. Besides, it has an additional data-ready signal, labeled as REQ and routed on the INT pin of the mikroBUS™ socket, indicating that new data is ready for the host. This Click board™ comes with worldwide regulatory certifications and offers enhanced performance, security, and reliability to support IoT products running on Bluetooth networks. Besides, at the center of the BLE 12 Click, an additional unpopulated header offers full

support for debugging and programming capabilities. With this header, the user can use a Serial Wire Debug interface for programming and debugging, available through the SWD interface pins (SWDIO, SWCLK, and SWO). In addition to the appropriate interfaces, this Click board™ also has some additional features. A Reset button routed to the RST pin on the mikroBUS™ socket puts the module into a Reset state, while the two additional LED indicators, yellow and red LEDs labeled as LED1 and LED2, can be used for optional user-configurable visual indication. 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.

BLE 12 Click hardware overview image

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 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.

EasyAVR v7 horizontal image

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

4096

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PA6
RST
SPI Chip Select
PA5
CS
SPI Clock
PB7
SCK
SPI Data OUT
PB6
MISO
SPI Data IN
PB5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Communication Selection
PD4
PWM
Data-Ready
PD2
INT
UART TX
PD1
TX
UART RX
PD0
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

BLE 12 Click Schematic schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

EasyAVR v7 front image hardware assembly
Buck 22 Click front image hardware assembly
MCU DIP 40 hardware assembly
EasyAVR v7 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
EasyPIC PRO v7a Display Selection Necto Step 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 BLE 12 Click driver.

Key functions:

  • ble12_set_device_name - BLE 12 set device name function

  • ble12_set_op_mode - BLE 12 set operating mode function

  • ble12_send_cmd - BLE 12 sends the command 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 main.c
 * @brief BLE 12 Click Example.
 *
 * # Description
 * This example reads and processes data from BLE 12 Click board™.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes UART driver and logs UART. 
 * After driver initialization, the app performs a wake-up module, 
 * enters command mode, sets the device name and advertising time interval, 
 * and disconnects all connections. 
 * After that, the blinking of the yellow LED Indicates
 * that the BLE 12 Click board™ is ready for connection. 
 * After establishing the connection, the yellow LED is turned on.
 *
 * ## Application Task
 * This example demonstrates the use of the BLE 12 Click board™. 
 * Reads the received data and parses it. 
 * Results are being sent to the Usart Terminal, where you can track their changes.
 *
 * ## Additional Function
 * - static void ble12_clear_app_buf ( void )
 * - static err_t ble12_process ( void )
 *
 * @note
 * We have used the Serial Bluetooth Terminal Android application for the test
 * and you can find it at the link:
 * https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal
 * 
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "ble12.h"

#define PROCESS_BUFFER_SIZE 200
#define RSP_TIMEOUT         100

static ble12_t ble12;
static log_t logger;

static char app_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;
static int32_t app_buf_cnt = 0;

/**
 * @brief BLE 12 clearing application buffer.
 * @details This function clears memory of application buffer and reset it's length and counter.
 * @note None.
 */
static void ble12_clear_app_buf ( void );

/**
 * @brief BLE 12 data reading function.
 * @details This function reads data from device and concatenates data to application buffer.
 *
 * @return @li @c  0 - Read some data.
 *         @li @c -1 - Nothing is read.
 *         @li @c -2 - Application buffer overflow.
 *
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t ble12_process ( void );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ble12_cfg_t ble12_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.
    ble12_cfg_setup( &ble12_cfg );
    BLE12_MAP_MIKROBUS( ble12_cfg, MIKROBUS_1 );
    if ( UART_ERROR == ble12_init( &ble12, &ble12_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( BLE12_ERROR == ble12_default_cfg ( &ble12 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    app_buf_len = 0;
    app_buf_cnt = 0;
    Delay_ms( 100 );
    log_info( &logger, " Application Task " );
    
    log_printf( &logger, "-------------------------------\r\n" );
    log_printf( &logger, "\t  BLE 12 Click\r\n" );
    log_printf( &logger, "-------------------------------\r\n" );
    log_printf( &logger, "\t  Command mode\r\n" );
    ble12_set_op_mode( &ble12, BLE12_OP_MODE_CMD );
    Delay_ms( 100 );
    
    ble12_event_startup( &ble12 );
    Delay_ms( 100 );
     
    ble12_set_led_state( &ble12, BLE12_LED_RED, BLE12_LED_OFF );
    ble12_set_led_state( &ble12, BLE12_LED_YELLOW, BLE12_LED_OFF );
    Delay_ms( 100 );
    
    log_printf( &logger, "- - - - - - - - - - - - - - - -\r\n" );
    log_printf( &logger, "> Set device name:" );
    log_printf( &logger, " BLE 12 Click\r\n" );
    ble12_set_device_name( &ble12, "BLE 12 Click" );
    Delay_ms( 100 );
    
    log_printf( &logger, "> Set Adv. Interval: 99 ms\r\n" );
    ble12_set_adv_interval( &ble12, "0099" );
    Delay_ms( 100 );
    
    log_printf( &logger, "> Disconnect all connections\r\n" );
    ble12_disconnect( &ble12 );
    Delay_ms( 100 );
    
    log_printf( &logger, "-------------------------------\r\n" );
    log_printf( &logger, "  Please connect your device\r\n" );
    
    do
    {
        ble12_process(); 
        ble12_set_led_state( &ble12, BLE12_LED_YELLOW, BLE12_LED_ON );
        Delay_ms( 50 );
        ble12_set_led_state( &ble12, BLE12_LED_YELLOW, BLE12_LED_OFF );
        Delay_ms( 50 );
    }
    while ( !strstr( app_buf, BLE12_EVT_CONNECTED ) );
    Delay_ms( 100 );

    ble12_set_led_state( &ble12, BLE12_LED_RED, BLE12_LED_OFF );
    ble12_set_led_state( &ble12, BLE12_LED_YELLOW, BLE12_LED_ON );
    log_printf( &logger, "- - - - - - - - - - - - - - - -\r\n" );
    log_printf( &logger, "\tDevice connected\r\n" );
    Delay_ms( 100 );
    
    ble12_set_op_mode( &ble12, BLE12_OP_MODE_DATA );
    log_printf( &logger, "-------------------------------\r\n" );
    log_printf( &logger, "\t    Data mode\r\n" );
    log_printf( &logger, "- - - - - - - - - - - - - - - -\r\n" );
    Delay_ms( 100 );
    
    ble12_process();
    ble12_clear_app_buf( );
    Delay_ms( 100 );
}

void application_task ( void ) 
{      
    ble12_process();
    
    if ( app_buf_len > 0 ) 
    { 
        log_printf( &logger, "%s", app_buf );
        ble12_clear_app_buf(  );    
    }
}

void main ( void ) 
{
    application_init( );

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

static void ble12_clear_app_buf ( void ) 
{
    memset( app_buf, 0, app_buf_len );
    app_buf_len = 0;
    app_buf_cnt = 0;
}

static err_t ble12_process ( void ) 
{
    int32_t rx_size;
    char rx_buff[ PROCESS_BUFFER_SIZE ] = { 0 };
    
    rx_size = ble12_generic_read( &ble12, rx_buff, PROCESS_BUFFER_SIZE );

    if ( rx_size > 0 ) 
    {
        int32_t buf_cnt = 0;

        if ( app_buf_len + rx_size >= PROCESS_BUFFER_SIZE ) 
        {
            ble12_clear_app_buf(  );
            return BLE12_ERROR;
        } 
        else
        {
            buf_cnt = app_buf_len;
            app_buf_len += rx_size;
        }

        for ( int32_t rx_cnt = 0; rx_cnt < rx_size; rx_cnt++ ) 
        {
            if ( ( rx_buff[ rx_cnt ] != 0 ) && ( rx_buff[ rx_cnt ] != 0x2B ) ) 
            {
                app_buf[ ( buf_cnt + rx_cnt ) ] = rx_buff[ rx_cnt ];   
            }
            else
            {
                app_buf_len--;
                buf_cnt--;
            }
        }
        
        
        
        return BLE12_OK;
    }
    return BLE12_ERROR;
}



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

Additional Support

Resources

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