FM Click

FM Click with it’s Si4703 IC is a complete FM radio tuner in the form of add-on board. It supports worldwide FM band (76 – 108 MHz).

Click Product page

Click library

• Author : MikroE Team
• Date : Jan 2020.
• Type : I2C type

Software Support

We provide a library for the Fm 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 form compilers IDE(recommended way), or downloaded from our LibStock, or found on mikroE github account.

Library Description

This library contains API for Fm Click driver.

Standard key functions :

• Config Object Initialization function.

  void fm_cfg_setup ( fm_cfg_t *cfg );

• Initialization function.

  FM_RETVAL fm_init ( fm_t ctx, fm_cfg_t cfg );

• Click Default Configuration function.

  void fm_default_cfg ( fm_t *ctx );

Example key functions :

• This function reads recived signal strength indicatior

  uint8_t fm_get_received_signal_strength_indicator ( fm_t *ctx );

• This function calculates current channel frequency based on band and space settings

  float fm_get_channel_frequency ( fm_t *ctx );

• This function reads CHANNEL bits from READCHAN register

  uint16_t fm_get_channel ( fm_t *ctx );

Examples Description

This Click represent FM radio tuner which supports worldwide FM band (76 – 108 MHz) and has a set of features such as automatic frequency and gain control, seek tuning and volume control.

The demo application is composed of two sections :

Application Init

Initializing I2C driver, powering up device, setting basic settings for Europe, setting values of seek threshold, volume, snr threshold and impulse detection threshold. Seek and memorize 5 radio stations with a signal strength above the set limit.

void application_init ( void )
{
    log_cfg_t log_cfg;
    fm_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.

    fm_cfg_setup( &cfg );
    FM_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    fm_init( &fm, &cfg );

    Delay_ms ( 500 );
    fm_default_cfg( &fm );

    memory = 0;
    mute = 0;
    fm_case_mute( &fm );

    for ( cnt = 0; cnt < 5;  )
    {
        log_printf( &logger, "seeking...\r\n" );
        do 
        {
            received_signal_strength_indicator = 0;
            fm_case_seek( &fm );
        }
        while ( received_signal_strength_indicator < SIGNAL_STRENGTH_LOWER_LIMIT ); //rssi value

        log_printf( &logger, "station found\r\n" );
        log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );
        log_printf( &logger, "channel frequency: %.2f MHz\r\n", channel_frequency );
        fm_case_memorize( );
        log_printf( &logger, "-----------------------\r\n" );
        Delay_ms ( 100 );
        cnt++;
    }  

    mute = 1;
    fm_case_mute( &fm );
    log_printf( &logger, "playing memorized stations...\r\n\r\n" );
}

Application Task

Tunes all memorized stations. Switches the stations each 10 seconds.

void application_task ( void )
{ 
    fm_case_station_1( &fm );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    fm_case_station_2( &fm );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    fm_case_station_3( &fm );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    fm_case_station_4( &fm );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    fm_case_station_5( &fm );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

The full application code, and ready to use projects can be installed directly form compilers IDE(recommneded) or found on LibStock page or mikroE GitHub accaunt.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Fm

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. The terminal available in all Mikroelektronika compilers, or any other terminal application of your choice, can be used to read the message.