使用Si4703和PIC18F46K20保持信息畅通和娱乐

调频，调高音量，尽情摇滚！

已发布 6月 26, 2024

点击板

FM Click

开发板

EasyPIC v8

编译器

NECTO Studio

微控制器单元

PIC18F46K20

只需插上耳机，无论你身在何处，都可以收听你喜爱的电台！

硬件概览

它是如何工作的？

FM Click基于Si4703，这是一款来自Silicon Labs的广播FM收音机调谐器。该收音机在全球范围内的FM波段工作，频率范围为76-108MHz，天线使用耳机。立体声音频连接器支持三和四导线耳机，建议电缆长度为1.1m至1.45m，以获得最佳信号接收效果。Si4703是行业中体积最小的FM调谐器之一，配备了32.768kHz的参考时钟，以获得更好的频率容差。它具有左右两个音频输出。每个输出使用来自德州仪器

的音频功率放大器LM4864来放大通道输出。这些放大器可以提供大约200mW的连续平均功率到8Ω负载。FM Click也可以作为立体声设备和单声道使用。FM Click可以通过mikroBUS™插座的I2C串行接口与主机MCU通信。除了通信引脚之外，此板还使用了其他几个引脚。SEN引脚路由到mikroBUS™插座的CS引脚，用作串行接口激活信号，与I2C引脚结合使用，形成3线接口。RST引脚用作通用复位功能，另外还有两

个用户可配置的引脚，GP2和GP1，路由到mikroBUS™插座的AN和INT引脚。这些I/O引脚可以用作中断请求（搜索/调谐或RDS准备）或立体声/单声道指示器。这个Click板™只能使用3.3V逻辑电压电平操作。在使用具有不同逻辑电平的MCU之前，板子必须执行适当的逻辑电压电平转换。但是，该Click板™配备了一个包含函数和示例代码的库，可用作进一步开发的参考。

功能概述

开发板

EasyPIC v8 是一款专为快速开发嵌入式应用的需求而特别设计的开发板。它支持许多高引脚计数的8位PIC微控制器，来自Microchip，无论它们的引脚数量如何，并且具有一系列独特功能，例如首次集成的调试器/程序员。开发板布局合理，设计周到，使得最终用户可以在一个地方找到所有必要的元素，如开关、按钮、指示灯、连接器等。得益于创新的制造技术，EasyPIC v8 提供了流畅而沉浸式的工作体验，允许在任何情况下、任何地方、任何时候都能访问。

EasyPIC v8 开发板的每个部分都包含了使同一板块运行最高效的必要组件。除了先进的集成CODEGRIP程序/调试模块，该模块提供许多有价值的编程/调试选项和与Mikroe软件环境的无缝集成外，该板还包括一个干净且调节过的开发板电源供应模块。它可以使用广泛的外部电源，包括电池、外部12V电源供应和通过USB Type-C（USB-C）连接器的电源。通信选项如USB-UART、USB DEVICE和CAN也包括在内，包括广受好评的mikroBUS™标准、两种显示选项（图形和

基于字符的LCD）和几种不同的DIP插座。这些插座覆盖了从最小的只有八个至四十个引脚的8位PIC MCU的广泛范围。EasyPIC v8 是Mikroe快速开发生态系统的一个组成部分。它由Mikroe软件工具原生支持，得益于大量不同的Click板™（超过一千块板），其数量每天都在增长，它涵盖了原型制作和开发的许多方面。

微控制器概述

MCU卡片 / MCU

建筑

PIC

MCU 内存 (KB)

硅供应商

Microchip

引脚数

RAM (字节)

3936

你完善了我！

配件

这款标准小型立体声耳机采用顶级立体声电缆和连接器，为用户提供高品质的听觉体验。设计通用兼容性，它们轻松连接到所有MIKROE mikromedia和多媒体板，是您电子项目的理想选择。耳机额定功率为100mW，能够在20Hz至20kHz的广泛频率范围内提供清晰的音频。它们具有100 ± 5dB的灵敏度和32Ω ± 15%的阻抗，确保了最佳的音质。直径为Φ15mm的扬声器提供清晰、沉浸式的音频。这些耳机具有性价比高、多功能的特点，非常适合测试您的原型设备，为您的项目提供经济实惠、可靠的音频解决方案。

使用的MCU引脚

mikroBUS™映射器

General Purpose I/O

RA2

Reset

RE1

RST

Serial Enable Input

RE0

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

General Purpose I/O

RB0

INT

Serial Clock Input

RC3

SCL

Serial Data Input

RC4

SDA

Ground

GND

“仔细看看！”

Click board™ 原理图

一步一步来

项目组装

EasyPIC v8 front image hardware assembly

从选择您的开发板和Click板™开始。以EasyPIC v8作为您的开发板开始。

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

EasyPIC v8 Access DIPMB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

NECTO Output Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

实时跟踪您的结果

应用程序输出

1. 应用程序输出 - 在调试模式下，“应用程序输出”窗口支持实时数据监控，直接提供执行结果的可视化。请按照提供的教程正确配置环境，以确保数据正确显示。

2. UART 终端 - 使用UART Terminal通过USB to UART converter监视数据传输，实现Click board™与开发系统之间的直接通信。请根据项目需求配置波特率和其他串行设置，以确保正常运行。有关分步设置说明，请参考提供的教程。

3. Plot 输出 - Plot功能提供了一种强大的方式来可视化实时传感器数据，使趋势分析、调试和多个数据点的对比变得更加直观。要正确设置，请按照提供的教程，其中包含使用Plot功能显示Click board™读数的分步示例。在代码中使用Plot功能时，请使用以下函数：plot(insert_graph_name, variable_name);。这是一个通用格式，用户需要将“insert_graph_name”替换为实际图表名称，并将“variable_name”替换为要显示的参数。

软件支持

库描述

这个库包含FM Click驱动程序的API。

关键功能:

fm_get_received_signal_strength_indicator - 此函数读取接收信号强度指示器
fm_get_channel_frequency - 此函数根据波段和间距设置计算当前频道频率
fm_get_channel - 此函数从READCHAN寄存器读取CHANNEL位

开源

代码示例

完整的应用程序代码和一个现成的项目可以通过NECTO Studio包管理器直接安装到NECTO Studio。应用程序代码也可以在MIKROE的GitHub账户中找到。

/*!
 * \file 
 * \brief Fm Click example
 * 
 * # 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.
 * 
 * ## Application Task  
 * Tunes all memorized stations. Switches the stations each 10 seconds.
 * 
 * ## Additional Functions
 * - void fm_case_plus( fm_t *ctx )      - Increases volume
 * - void fm_case_minus( fm_t *ctx )     - Decreases volume
 * - void fm_case_seek( fm_t *ctx )      - Seeks next station
 * - void fm_case_tune( fm_t *ctx )      - Tunes default station
 * - void fm_case_memorize( )            - Memorizes current station
 * - void fm_case_station1( fm_t *ctx )  - Tunes memorized station 1
 * - void fm_case_station2( fm_t *ctx )  - Tunes memorized station 2
 * - void fm_case_station3( fm_t *ctx )  - Tunes memorized station 3
 * - void fm_case_station4( fm_t *ctx )  - Tunes memorized station 4
 * - void fm_case_station5( fm_t *ctx )  - Tunes memorized station 5
 * - void fm_case_mute( fm_t *ctx )      - Mutes device
 * - void fm_case_tune_up( fm_t *ctx )   - Fine tunes frequency
 * - void fm_case_tune_down( fm_t *ctx ) - Fine tunes frequency
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "fm.h"

// ------------------------------------------------------------------ VARIABLES

#define SIGNAL_STRENGTH_LOWER_LIMIT 25

static fm_t fm;
static log_t logger;

static uint16_t received_signal_strength_indicator;
static uint16_t station_channel;
static uint16_t station1;
static uint16_t station2;
static uint16_t station3;
static uint16_t station4;
static uint16_t station5;

static uint8_t memory;
static uint8_t mute;
static uint8_t received_data;
static uint8_t data_ready;
static uint8_t error_flag;
static uint8_t cnt;

static float channel_frequency;
static float tuned_frequency;
static float tune_freq;

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

void fm_case_plus ( fm_t *ctx  )
{
    error_flag = fm_volume_up( ctx );

    if ( error_flag == 0 )
    {
        log_printf( &logger, "volume up\r\n" );
    }
    else
    {
        log_printf( &logger, "volume max\r\n" );
    }
}

void fm_case_minus ( fm_t *ctx )
{
    error_flag = fm_volume_down( ctx );

    if ( error_flag == 0 )
    {
        log_printf( &logger, "volume down\r\n" );
    }
    else
    {
        log_printf( &logger, "volume min\r\n" );
    }
}

void fm_case_seek ( fm_t *ctx )
{
    fm_seek( ctx );

    Delay_ms( 500 );

    fm_end_seek( ctx );

    Delay_ms( 10 );

    received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
    channel_frequency = fm_get_channel_frequency( ctx );
    station_channel = fm_get_channel( ctx );
}

void fm_case_tune ( fm_t *ctx )
{
    error_flag = fm_tune( ctx, tune_freq );

    Delay_ms( 100 );

    fm_end_tune( ctx );

    Delay_ms( 10 );

    if ( error_flag == 0 )
    {
        received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
        tuned_frequency = fm_get_channel_frequency( ctx );
        station_channel = fm_get_channel( ctx );

        log_printf( &logger, "tune complete\r\n" );

        log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

        log_printf( &logger, "tuned frequency: %.2f MHz\r\n", tuned_frequency );
        log_printf( &logger, "-----------------------\r\n" );
    }
    else
    {
        log_printf( &logger, "frequency not in valid range\r\n" );
    }
}

void fm_case_memorize ( )
{
    switch ( memory )
    {
        case 0 :
        {
            station1 = station_channel;
            memory += 1;

            log_printf( &logger, "station 1 memorized\r\n" );

            break;
        }
        case 1 :
        {
            station2 = station_channel;
            memory += 1;

            log_printf( &logger, "station 2 memorized\r\n" );

            break;
        }
        case 2 :
        {
            station3 = station_channel;
            memory += 1;

            log_printf( &logger, "station 3 memorized\r\n" );
            
            break;
        }
        case 3 :
        {
            station4 = station_channel;
            memory += 1;

            log_printf( &logger, "station 4 memorized\r\n" );

            break;
        }
        case 4 :
        {
            station5 = station_channel;
            memory = 0;

            log_printf( &logger, "station 5 memorized\r\n" );

            break;
        }
        default :
        {
            break;
        }
    }
}

void fm_case_mute ( fm_t *ctx )
{
    if ( mute == 0 )
    {
        fm_mute_enable( ctx );

        log_printf( &logger, "mute enabled\r\n" );

        mute = 1;
    }
    else if ( mute == 1 )
    {
        fm_mute_disable( ctx );

        log_printf( &logger, "mute disabled\r\n" );

        mute = 0;
    }
}

void fm_case_station_1 ( fm_t *ctx  )
{
    fm_tune_channel( ctx, station1 );

    Delay_ms( 100 );

    fm_end_tune( ctx );

    Delay_ms( 10 );

    received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
    channel_frequency = fm_get_channel_frequency( ctx );

    log_printf( &logger, "station 1 tuned\r\n" );

    log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

    log_printf( &logger, "tuned frequency: %.2f MHz\r\n", channel_frequency );
    log_printf( &logger, "-----------------------\r\n" );
}

void fm_case_station_2 ( fm_t *ctx )
{
    fm_tune_channel( ctx, station2 );

    Delay_ms( 100 );

    fm_end_tune( ctx );

    Delay_ms( 10 );

    received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
    channel_frequency = fm_get_channel_frequency( ctx );

    log_printf( &logger, "station 2 tuned\r\n" );

    log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

    log_printf( &logger, "tuned frequency: %.2f MHz\r\n", channel_frequency );
    log_printf( &logger, "-----------------------\r\n" );
}

void fm_case_station_3 ( fm_t *ctx )
{
    fm_tune_channel( ctx, station3 );

    Delay_ms( 100 );

    fm_end_tune( ctx );

    Delay_ms( 10 );

    received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
    channel_frequency = fm_get_channel_frequency( ctx );

    log_printf( &logger, "station 3 tuned\r\n" );

    log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

    log_printf( &logger, "tuned frequency: %.2f MHz\r\n", channel_frequency );
    log_printf( &logger, "-----------------------\r\n" );
}

void fm_case_station_4 ( fm_t *ctx )
{
    fm_tune_channel( ctx, station4 );

    Delay_ms( 100 );

    fm_end_tune( ctx );

    Delay_ms( 10 );

    received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
    channel_frequency = fm_get_channel_frequency( ctx );

    log_printf( &logger, "station 4 tuned\r\n" );

    log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

    log_printf( &logger, "tuned frequency: %.2f MHz\r\n", channel_frequency );
    log_printf( &logger, "-----------------------\r\n" );
}

void fm_case_station_5 ( fm_t *ctx )
{
    fm_tune_channel( ctx, station5 );

    Delay_ms( 100 );

    fm_end_tune( ctx );

    Delay_ms( 10 );

    received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
    channel_frequency = fm_get_channel_frequency( ctx );

    log_printf( &logger, "station 5 tuned\r\n" );

    log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

    log_printf( &logger, "tuned frequency: %.2f MHz\r\n", channel_frequency );
    log_printf( &logger, "-----------------------\r\n" );
}

void fm_case_tune_up ( fm_t *ctx )
{
    error_flag = fm_fine_tune_up( ctx );

    if ( error_flag == 0 )
    {
        Delay_ms( 100 );

        fm_end_tune( ctx );

        Delay_ms( 10 );
        
        received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
        channel_frequency = fm_get_channel_frequency( ctx );
        station_channel = fm_get_channel( ctx ); 

        log_printf( &logger, "tune up\r\n" );

        log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

        log_printf( &logger, "tuned frequency: %.2f MHz\r\n", channel_frequency );
        log_printf( &logger, "-----------------------\r\n" );
    }
    else
    {
        log_printf( &logger, "upper band limit reached\r\n" );
    }
}

void fm_case_tune_down ( fm_t *ctx )
{
    error_flag = fm_fine_tune_down( ctx );

    if ( error_flag == 0 )
    {
        Delay_ms( 100 );

        fm_end_tune( ctx );

        Delay_ms( 10 );
    
        received_signal_strength_indicator = fm_get_received_signal_strength_indicator( ctx );
        channel_frequency = fm_get_channel_frequency( ctx );
        station_channel = fm_get_channel( ctx );

        log_printf( &logger, "tune down\r\n" );

        log_printf( &logger, "rssi: %u dBuV\r\n", received_signal_strength_indicator );

        log_printf( &logger, "tuned frequency: %.2f MHz\r\n", channel_frequency );
        log_printf( &logger, "-----------------------\r\n" );
    }
    else
    {
        log_printf( &logger, "lower band limit reached\r\n" );
    }
}

void fm_case_wrong_command ( )
{
    log_printf( &logger, "wrong command\r\n" );
}

// ------------------------------------------------------ APPLICATION FUNCTIONS

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" );
}

void application_task ( void )
{ 
    fm_case_station_1( &fm );
    Delay_ms( 10000 );
       
    fm_case_station_2( &fm );
    Delay_ms( 10000 );
    
    fm_case_station_3( &fm );
    Delay_ms( 10000 );
    
    fm_case_station_4( &fm );
    Delay_ms( 10000 );
    
    fm_case_station_5( &fm );
    Delay_ms( 10000 );
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END