fm.c

飞利浦公司的芯片

#include "STC89C51RC_RD_PLUS.H"
#include "FM.h"
#include "System.h"
#include "iic.h"
#include   <intrins.h>
//RF发射具体数据，接受到以后，按照相应数据写入即可。没有手动，自动搜台功能
#define max_freq 108000
#define min_freq 87500
unsigned char radio_write_data[5]={0x29,0xc2,0x20,0x11,0x00};  //要写入TEA5767的数据87.8MHZ
unsigned char radio_read_data[5];        							//TEA5767读出的状态
unsigned int pll;
unsigned long frequency=87700;

void radio_write(void)
{
    unsigned char i;
    IICStart();
    IICWriteByte(0xc0);        									//TEA5767写地址
    if(!IICRecAck())
    {
        for(i=0;i<5;i++)
        {
            IICWriteByte(radio_write_data[i]);
            IICACK();
        }
    }
    IICStop();    
}

//读TEA5767状态,并转换成频率
void radio_read(void)
{
    unsigned char i;
    unsigned char temp_l,temp_h;
    pll=0;
    IICStart();
    IICWriteByte(0xc1);        									//TEA5767读地址
    if(!IICRecAck())
    {
        for(i=0;i<5;i++)
        {
            radio_read_data[i]=IICReadByte();
            IICACK();
        }
    }
    IICStop();
    temp_l=radio_read_data[1];
    temp_h=radio_read_data[0];
    temp_h&=0x3f;
    pll=temp_h*256+temp_l;
    get_frequency();
}

//由频率计算PLL
void get_pll(void)
{
    unsigned int twpll=0;
    pll=(unsigned int)((float)((frequency-225)*4)/(float)32.768);    //频率单位:k
}
//由PLL计算频率
void get_frequency(void)
{
    unsigned int npll=0;
    npll=pll;
    frequency=(unsigned long)((float)(npll)*(float)8.192+225);    //频率单位:KHz
}

//手动设置频率,mode=1,+0.1MHz; mode=0:-0.1MHz ,不用考虑TEA5767用于搜台的相关位:SM,SUD
void search(bit mode)
{
    radio_read();     												  //读TEA5767 PLL 状态,并转换成频率   
    if(mode)
    {
        frequency+=100;
        if(frequency>max_freq)
            frequency=min_freq;
    }
    else
    {
        frequency-=100;
        if(frequency<min_freq)
            frequency=max_freq;
    }          
    get_pll();														 //由频率计算PLL
    radio_write_data[0]=pll/256;
    radio_write_data[1]=pll%256;
    radio_write_data[2]=0xe0;
    radio_write_data[3]=0x11;
    radio_write_data[4]=0x00;
    radio_write();
}

unsigned long Get_Frequence(void)
{
	return(frequency);
}

//自动搜台,mode=1,频率增加搜台; mode=0:频率减小搜台,不过这个好像不能循环搜台
void auto_search(bit mode)
{
    radio_read();
    get_pll();
    if(mode)
        radio_write_data[2]=0xa0;
    else
        radio_write_data[2]=0x20;    
    radio_write_data[0]=pll/256+0x40;
    radio_write_data[1]=pll%256;    
    radio_write_data[3]=0x11;
    radio_write_data[4]=0x00;
    radio_write();
    radio_read();
    while(!(radio_read_data[0]&0x80))     //搜台成功标志
    {
        radio_read();
    }    
}