BM78 Click

BM78 Click is a compact add-on board designed to integrate dual-mode Bluetooth wireless capability into various projects. This board features the BM78, a fully certified 2.4GHz Bluetooth (BR/EDR/LE) wireless module from Microchip. The BM78 module includes an on-board Bluetooth stack, power management subsystem, 2.4GHz transceiver, and RF power amplifier. It supports GAP, SDP, SPP, and GATT profiles, with data transfer facilitated through transparent UART mode. It features a MODE SEL switch for operational modes, a reset pin, status indicators, a software power button, and a WAKE button.

Click Product page

Click library

• Author : Stefan Ilic
• Date : Feb 2024.
• Type : UART type

Software Support

We provide a library for the BM78 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for BM78 Click driver.

Standard key functions :

• bm78_cfg_setup Config Object Initialization function.

  void bm78_cfg_setup ( bm78_cfg_t *cfg );

• bm78_init Initialization function.

  err_t bm78_init ( bm78_t *ctx, bm78_cfg_t *cfg );

Example key functions :

• bm78_eeprom_send_cmd This function is used to send specific EEPROM command by using UART serial interface.

  err_t bm78_eeprom_send_cmd ( bm78_t *ctx, uint16_t op_code, uint8_t *param, uint8_t len );

• bm78_eeprom_write This function is used to write data into the EEPROM location specified by the address parameter.

  err_t bm78_eeprom_write ( bm78_t *ctx, uint16_t address, uint8_t *data_in, uint8_t len );

• bm78_flash_eeprom This function is used write default configuration into the EEPROM.

  err_t bm78_flash_eeprom ( bm78_t *ctx );

Example Description

This example demonstrates the use of BM78 Click board by processing the incoming data and displaying them on the USB UART.

The demo application is composed of two sections :

Application Init

Initializes the driver and performs the Click default configuration by writing it into the EEPROM.

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    bm78_cfg_t bm78_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.
    bm78_cfg_setup( &bm78_cfg );
    BM78_MAP_MIKROBUS( bm78_cfg, MIKROBUS_1 );
    if ( UART_ERROR == bm78_init( &bm78, &bm78_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    uint8_t tmp_data[ 16 ];
    bm78_generic_read( &bm78, &tmp_data, 1 );  
    Delay_ms ( 100 );

    log_printf( &logger, " = = = = = = = = = = = = = = = = = \r\n" );
    log_printf( &logger, " Place Click into Write EEPROM mode \r\n" );
    log_printf( &logger, " By setting MODE SEL in the following configuration \r\n" );
    log_printf( &logger, "         | 1 | 2 | 3 |             \r\n" );
    log_printf( &logger, "         | H | L | L |             \r\n" );
    log_printf( &logger, " = = = = = = = = = = = = = = = = = \r\n" );
    log_printf( &logger, " Send YES once you placed Click into Write EEPROM mode \r\n" );
    #define WANTED_ANSWER "YES/r/n"
    log_printf( &logger, " = = = = = = = = = = = = = = = = = \r\n" );
    while ( 1 )
    {
        log_read( &logger, &tmp_data, 5 );

        if ( 0 == strstr ( WANTED_ANSWER, tmp_data ) )
        {
            break;
        }
        else
        {
            log_printf( &logger, " Send YES once you placed Click into Write EEPROM mode \r\n" );
        }
    }
    bm78_hw_reset( &bm78 );
    log_printf( &logger, " Writing into the EEPROM \r\n" );
    if ( BM78_ERROR == bm78_flash_eeprom ( &bm78 ) )
    {
        log_error( &logger, " EEPROM Flash failed. " );
        log_printf( &logger, " Check Selected Click mode. \r\n" );
        for ( ; ; );
    }

    log_printf( &logger, " = = = = = = = = = = = = = = = = = \r\n" );
    log_printf( &logger, " Place Click into Application mode \r\n" );
    log_printf( &logger, " By setting MODE SEL in the following configuration \r\n" );
    log_printf( &logger, "         | 1 | 2 | 3 |             \r\n" );
    log_printf( &logger, "         | L | L | L |             \r\n" );
    log_printf( &logger, " = = = = = = = = = = = = = = = = = \r\n" );
    log_printf( &logger, " Send YES once you placed Click into Application mode \r\n" );
    log_printf( &logger, " = = = = = = = = = = = = = = = = = \r\n" );
    while ( 1 )
    {
        log_read( &logger, &tmp_data, 5 );

        if ( 0 == strstr ( WANTED_ANSWER, tmp_data ) )
        {
            break;
        }
        else
        {
            log_printf( &logger, " Send YES once you placed Click into Application mode \r\n" );
        }
    }
    bm78_hw_reset( &bm78 );

    log_info( &logger, " Application Task " );
    log_printf( &logger, " Connect to the device using the Serial Bluetooth Terminal App \r\n\r\n" );
}

Application Task

Reads and processes all incoming data from the Serial Bluetooth Terminal smartphone application and displays them on the USB UART.

void application_task ( void ) 
{
    if ( BM78_OK == bm78_process( &bm78 ) ) 
    {
        bm78_log_app_buf( );
        bm78_clear_app_buf( );
    }
}

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.

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.BM78

Additional notes and informations

Depending on the development board you are using, you may need USB UART Click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.