Library Description

The library covers all the necessary functions to control MP3 2 Click board. A library performs the communication with the KT403A chip which integrate 16-bit MCU, and audio decoder, a DSP especial for decoding via UART interface.

Key functions:

• void mp32_play_mode ( void ) - Play mode function.
• void mp32_play_next ( void ) - Play next function.
• void mp32_volume_up ( void ) - Volume up function.

Examples description

The application is composed of three sections :

• System Initialization - Initializes UART, RST pin as output and begins to write log.
• Application Initialization - Initialization driver enables - UART, reset the device, set specify a device play tracks inside ( SD Card ), set volume lvl ( 50% ), set equalizer to normal mode and set commmand for specifying a track to play.
• Application Task - (code snippet) This is an example which demonstrates the use of MP3 2 Click board. Waits for valid user input and executes functions based on set of valid commands. Results are being sent to the Usart Terminal where you can track their changes.
• Commands : 'c' - command list 'p' - play 'o' - pause 's' - stop 'n' - play next 'l' - play previous '+' - volume up '-' - volume down

void application_task ( )
{
    char received_data;

    if ( UART_Rdy_Ptr() )
    {
        received_data = UART_Rd_Ptr( );
     
        switch ( received_data )
        {
            case 'c' :
            {
                command_list( );
                break;
            }
            case 'p' :
            {
                mp32_play_mode( );
                mikrobus_logWrite( " >>> Play", _LOG_LINE );
                break;
            }
            case 'o' :
            {
                mp32_pause_mode( );
                mikrobus_logWrite( " >>> Pause", _LOG_LINE );
                break;
            }
            case 's' :
            {
                mp32_stop_mode( );
                mikrobus_logWrite( " >>> Stop", _LOG_LINE );
                break;
            }
            case 'n' :
            {
                mp32_play_next( );
                mikrobus_logWrite( " >>> Play next", _LOG_LINE );
                break;
            }
            case 'l' :
            {
                mp32_play_previous( );
                mikrobus_logWrite( " >>> Play previous", _LOG_LINE );
                break;
            }
            case '+' :
            {
                mp32_volume_up( );
                mikrobus_logWrite( " >>> Volume Up", _LOG_LINE );
                break;
            }
            case '-' :
            {
                mp32_volume_down( );
                mikrobus_logWrite( " >>> Volume Down", _LOG_LINE );
                break;
            }
            default :
            {
                command_list( );
                break;
            }
        }
    }

    Delay_ms( 1000 );
}

Key functions:

• command_list( ) - Display the list of commands.

Other mikroE Libraries used in the example:

• UART

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.