AM/FM 2 Click

AM/FM 2 Click is a compact add-on board that can be used to listen to music from the AM and FM radio bands. This board features the Si4732, a broadcast AM/FM/SE/LW/RDS radio receiver from Skyworks. This radio receiver integrates the complete broadcast tuner and receiver function from antenna input to digital audio output. In addition to the radio receiver, this Click board™ is equipped with the LM4910, a Boomer output capacitor-less stereo 35mW headphone amplifier from Texas Instruments. This amplifier can deliver 35mW of continuous average power to a 32Ω load with less than 1% distortion.

Click Product page

Click library

• Author : Nenad Filipovic
• Date : May 2023.
• Type : I2C type

Software Support

We provide a library for the AM/FM 2 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 AM/FM 2 Click driver.

Standard key functions :

• amfm2_cfg_setup Config Object Initialization function.

  void amfm2_cfg_setup ( amfm2_cfg_t *cfg );

• amfm2_init Initialization function.

  err_t amfm2_init ( amfm2_t *ctx, amfm2_cfg_t *cfg );

• amfm2_default_cfg Click Default Configuration function.

  err_t amfm2_default_cfg ( amfm2_t *ctx );

Example key functions :

• amfm2_seek_station AM/FM 2 seek station function.

  err_t amfm2_seek_station ( amfm2_t *ctx, uint8_t *rsp );

• amfm2_tuning_freq AM/FM 2 tuning frequency function.

  err_t amfm2_tuning_freq ( amfm2_t *ctx, float frequency, uint8_t *rsp );

• amfm2_get_tuning_freq AM/FM 2 get tuning frequency function.

  err_t amfm2_get_tuning_freq ( amfm2_t *ctx, float *frequency );

Example Description

This example demonstrates the use of the AM/FM 2 Click board™. The app represents a radio tuner that supports worldwide AM/FM bands and has features such as automatic frequency control, seek station, and volume control.

The demo application is composed of two sections :

Application Init

The initialization of I2C module and log UART. After driver initialization, the app sets the default configuration and searches and memorizes for a valid frequency of the 5 radio stations.

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    amfm2_cfg_t amfm2_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.
    amfm2_cfg_setup( &amfm2_cfg );
    AMFM2_MAP_MIKROBUS( amfm2_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == amfm2_init( &amfm2, &amfm2_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    if ( AMFM2_ERROR == amfm2_default_cfg ( &amfm2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    Delay_ms ( 100 );

    log_printf( &logger, " Begins searching for a valid frequency...\r\n" );
    log_printf( &logger, "--------------------\r\n" );
    for ( uint8_t n_cnt = 0; n_cnt < 5; n_cnt++ )
    {
        if ( AMFM2_OK == amfm2_seek_station( &amfm2, &rsp_status ) )
        {
            if ( AMFM2_RSP_STATUS_CTS & rsp_status )
            {
                log_printf( &logger, " The search is done.\r\n" );
                if ( AMFM2_OK == amfm2_get_tuning_freq( &amfm2, &mem_station_freq[ n_cnt ] ) )
                {
                    log_printf( &logger, " Frequency: %.2f MHz \r\n", mem_station_freq[ n_cnt ] );
                    log_printf( &logger, "- - - - - - - - - - \r\n" );
                    Delay_ms ( 100 );
                }
            }
        }
    }
    log_printf( &logger, "--------------------\r\n" );
    Delay_ms ( 100 );

    if ( AMFM2_OK == amfm2_set_volume( &amfm2, AMFM2_SET_VOLUME_MAX, &rsp_status ) )
    {
        log_printf( &logger, " Set max volume \r\n" );
        Delay_ms ( 100 );
    }

    log_info( &logger, " Application Task " );
    log_printf( &logger, "--------------------\r\n" );
    Delay_ms ( 100 );
}

Application Task

This example demonstrates the use of the AM/FM 2 Click board™. The application switches all 5 previously memorized radio frequencies every 10 seconds. Results are being sent to the UART Terminal, where you can track their changes.

void application_task ( void ) 
{
    for ( uint8_t n_cnt = 0; n_cnt < 5; n_cnt++ )
    {
        if ( AMFM2_OK == amfm2_tuning_freq( &amfm2, mem_station_freq[ n_cnt ], &rsp_status ) )
        {
            log_printf( &logger, " FM Station %d \r\nFrequency: %.2f MHz\r\n", 
                       ( uint16_t ) ( n_cnt + 1 ), mem_station_freq[ n_cnt ] );
            log_printf( &logger, "--------------------\r\n" );
            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 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.AMFM2

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.