Bluetooth 2 Click

Bluetooth 2 Click features WT41u, a long range class 1, Bluetooth® 2.1 + EDR module from Silicon Labs. WT41u is a highly integrated and sophisticated Bluetooth® module, containing all the necessary elements from Bluetooth® radio and a fully implemented protocol stack. Therefore WT41u provides an ideal solution for developers who want to integrate Bluetooth® wireless technology into their design with limited knowledge of Bluetooth® and RF technologies. WT41u optimized for long range applications is available with an integrated chip antenna.

Click Product page

Click library

• Author : Stefan Filipovic
• Date : Jun 2021.
• Type : UART type

Software Support

We provide a library for the Bluetooth2 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 Bluetooth2 Click driver.

Standard key functions :

• bluetooth2_cfg_setup Config Object Initialization function.

  void bluetooth2_cfg_setup ( bluetooth2_cfg_t *cfg );

• bluetooth2_init Initialization function.

  err_t bluetooth2_init ( bluetooth2_t *ctx, bluetooth2_cfg_t *cfg );

• bluetooth2_default_cfg Click Default Configuration function.

  void bluetooth2_default_cfg ( bluetooth2_t *ctx );

Example key functions :

• bluetooth2_factory_reset This function factory resets the device.

  err_t bluetooth2_factory_reset ( bluetooth2_t *ctx );

• bluetooth2_set_device_name This function sets the local device name.

  err_t bluetooth2_set_device_name ( bluetooth2_t *ctx, char *dev_name );

• bluetooth2_generic_write This function writes a desired number of data bytes by using UART serial interface.

  err_t bluetooth2_generic_write ( bluetooth2_t *ctx, char *data_buf, uint16_t len );

Example Description

This example reads and processes data from Bluetooth 2 clicks.

The demo application is composed of two sections :

Application Init

Initializes the driver, then performs a factory reset, removes all pairings, and sets the local device name.

void application_init ( void )
{
    log_cfg_t log_cfg;                /**< Logger config object. */
    bluetooth2_cfg_t bluetooth2_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 );
    Delay_ms ( 100 );
    log_info( &logger, " Application Init " );

    // Click initialization.

    bluetooth2_cfg_setup( &bluetooth2_cfg );
    BLUETOOTH2_MAP_MIKROBUS( bluetooth2_cfg, MIKROBUS_1 );
    err_t init_flag  = bluetooth2_init( &bluetooth2, &bluetooth2_cfg );
    if ( UART_ERROR == init_flag ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    bluetooth2_default_cfg ( &bluetooth2 );
    bluetooth2_process( );
    bluetooth2_clear_app_buf( );

    log_printf( &logger, " - Factory Reset -\r\n" );
    bluetooth2_factory_reset ( &bluetooth2 );
    bluetooth2_display_rsp ( 2000 ); 

    log_printf( &logger, " - Enable OK response -\r\n" );
    bluetooth2_enable_ok_response ( &bluetooth2 );
    bluetooth2_display_rsp ( 1000 ); 

    log_printf( &logger, " - Remove Pairings -\r\n" );
    bluetooth2_remove_pairings ( &bluetooth2 );
    bluetooth2_display_rsp ( 1000 ); 

    log_printf( &logger, " - Set Device Name -\r\n" );
    bluetooth2_set_device_name ( &bluetooth2, DEVICE_NAME );
    bluetooth2_display_rsp ( 1000 ); 

    log_info( &logger, " Application Task " );
}

Application Task

Logs all the received messages/responses on the USB UART, and if there's any device connected to the Click board the module sends a desired message every 5 seconds back to it.

void application_task ( void )
{
    bluetooth2_process();
    if ( app_buf_len > 0 ) 
    {
        Delay_ms ( 200 );
        bluetooth2_process();

        if ( strstr( app_buf, RSP_RING ) )
        {
            connection_flag = 1;
            send_cnt = 0;
        }
        if ( strstr( app_buf, RSP_NO_CARRIER ) )
        {
            connection_flag = 0;
            send_cnt = 0;
        }
        log_printf( &logger, "%s", app_buf );
        bluetooth2_clear_app_buf(  );
    }

    if ( connection_flag == 1 && send_cnt++ > SENDING_FREQ )
    {
        bluetooth2_generic_write( &bluetooth2, TEXT_TO_SEND, strlen( TEXT_TO_SEND ) );
        send_cnt = 0;
    }

    Delay_ms ( 1 );
}

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.Bluetooth2

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.