/*
  *	Source	: FMRadio10.c
  *	Date	: 2011/04/24
  *	Update	:
  *	Auther	: Pharaoh
  */
 
#include <p24FJ64GA002.h>
 

#define	TEA_BUSMODE		LATBbits.LATB7
#define	TEA_RW				LATBbits.LATB6
#define	TEA_CLK			LATBbits.LATB8
#define	TEA_DATA			LATBbits.LATB9

_CONFIG1(JTAGEN_OFF & GCP_OFF & GWRP_OFF & BKBUG_OFF & COE_OFF & ICS_PGx1 & FWDTEN_OFF)

// FNOSC_FRC : Fast RC Oscillator (8MHz)
// FCKSM_CSDCMD : Clock switching and clock monitor : disabled
// OSCIOFNC_OFF : 
// IOL1WAY_OFF : 
// I2C1SEL_PRI : Use Primary I2C1 pins (PIN 17 & 18)
// POSCMOD_NONE : Primary Oscillator disabled
_CONFIG2(IESO_OFF & FNOSC_FRC & FCKSM_CSDCMD & OSCIOFNC_OFF & IOL1WAY_OFF & I2C1SEL_PRI & POSCMOD_NONE)


void SendDataTo3Wire(unsigned char data);
void SelectStation(unsigned int freq);
void Wait(unsigned long t);


int main(void)
{
	
	// I Oの初期設定
	AD1PCFG = 0xFFFF;				// すべてデジタル
	CLKDIV = 0;						// 
	TRISA = 0xFFFF;					// RA0-4=すべて入力
	TRISB = 0xE003;					// RB2,3,4,5,6,7,8,910,11,12=出力(使うのは8,9,12)
	CNPU1 = 0x3830;				// CN4,5,11,12,13=Pull Up
	CNPU2 = 0;						// CN16〜=Pull Upなし
	CNEN1 = 0x3800;				// CN11,12,13=割り込み許可
	
	TEA_BUSMODE = 1;			// Bus Mode = 1 : 
	TEA_RW = 0;
	TEA_CLK = 0;
	TEA_DATA = 0;
	
	SelectStation(825);
	
	Sleep();			// 11/05/04
	while (1);
	
	return (0);
}

/*
 *	１バイトデータ転送
 */
void SendDataTo3Wire(unsigned char data)
{
	int		i;
	
	for (i=0; i<8; i++){
		if ((data & 0x80) == 0x80){
			TEA_DATA = 1;
		} else {
			TEA_DATA = 0;
		}
		data <<= 1;
		
		// CLK
		TEA_CLK = 1;
		Wait(100);
		TEA_CLK = 0;		
	}	
}

/*
 *	FM局選択
 *		freq : 0.1MHz単位
 */
void SelectStation(unsigned int freq)
{
	unsigned long	pll;
	unsigned char	d1, d2, d3, d4, d5;
	
	pll = 4000*(((unsigned long)freq)*100L + 225) / 32768;
	
	d1 = ((pll >> 8) & 0x3F);			// 1st byte : mute off, SM off
	d2 = (pll & 0xFF);					// 2nd byte
	d3 = 0x10;						// 3rd byte : High side injection, stereo, right mute off, left mute off
	d4 = 0x36;						// 4th byte
	d5 = 0x00;						// 5th byte
	
	TEA_RW = 0;
	TEA_CLK = 0;
	TEA_DATA = 0;
	
	TEA_RW = 1;
	
	SendDataTo3Wire(d1);
	SendDataTo3Wire(d2);
	SendDataTo3Wire(d3);
	SendDataTo3Wire(d4);
	SendDataTo3Wire(d5);
	
	TEA_RW = 0;
	TEA_CLK = 0;
	TEA_DATA = 0;
}


/*
 *	待ち
 */
void Wait(unsigned long t)
{
	while (t > 0){
		asm("nop");
		t--;
	}
}