技事新報

#include 
#include "adc10.h"
#include "timer.h"
#include "dsp.h"

// Configuration bits--------------------------------------------------------
_FOSC(CSW_FSCM_OFF & FRC_PLL16);   //FRC with 16xPLL oscillator, Failsafe clock off
_FWDT(WDT_OFF);                  //Watchdog timer disabled
_FBORPOR(PBOR_OFF & MCLR_EN);    //Brown-out reset disabled, MCLR reset enabled
_FGS(CODE_PROT_OFF);             //Code protect disabled

//// Setup Data for 10bits A/D Converter
//// AN0のみサンプル Tad=200nsec@40MHz
//// タイマ３で自動スタート, 自動スキャン無し
unsigned int ValueADCON1 = ADC_MODULE_ON & ADC_IDLE_STOP & ADC_FORMAT_INTG &
			ADC_CLK_TMR & ADC_AUTO_SAMPLING_ON & ADC_SAMPLE_INDIVIDUAL & 
			ADC_SAMP_OFF;
unsigned int ValueADCON2 = ADC_VREF_AVDD_AVSS & ADC_SCAN_OFF & ADC_CONVERT_CH0
			 & ADC_SAMPLES_PER_INT_1 & ADC_ALT_BUF_OFF & ADC_ALT_INPUT_OFF;
unsigned int ValueADCON3 = ADC_SAMPLE_TIME_1 & ADC_CONV_CLK_SYSTEM 
			 & ADC_CONV_CLK_2Tcy;
unsigned int ValueADPCFG = ENABLE_AN0_ANA & ENABLE_AN1_ANA & ENABLE_AN2_ANA
			 & ENABLE_AN3_ANA;
unsigned int ValueADCSSL = 0;
unsigned int Channel0 = ADC_CH0_POS_SAMPLEA_AN0 & ADC_CH0_NEG_SAMPLEA_NVREF;

// Definitions---------------------------------------------------------------
#define BUF_LEN 256
#define LPC_ORDER 4

//グローバル変数-----------------------------------------------------------------
long int lpc[LPC_ORDER+1];
long int in_buf[BUF_LEN];
long int out_buf[LPC_ORDER+1];
int ix_buf = 0;
int ix_read = 0;
int ix_write = 0;
int ratio = 0;
int s_cnt = 0;		//音程用
int zero_cnt = 0;
unsigned char sound = 0;

//// タイマ１割り込み処理（16k/256/2Hz)
void _ISR _T1Interrupt(void)
{
	int n,m,k;
	int i,j;
	long int r[LPC_ORDER+1];
	long int a[LPC_ORDER+1];
	long int b[LPC_ORDER+1];
	long int alfa;
	long int km,alfam,t;
	
	IFS0bits.T1IF = 0;
	
	//AutoCorrelation
	for(i=0; i<=LPC_ORDER; i++){
		r[i] = 0;
		for(j=0; j<(BUF_LEN-i); j++){
			r[i] += ((in_buf[j] * in_buf[j+i])>>8);
		}
	}

	//Levinson-Durbin
	a[0] = 1<<8;
	alfam = r[0];
	for(m=1; m<=LPC_ORDER; m++){
		t = r[m];
		for(k=1; k<=m-1; k++){
			t = t + ((r[m-k]*a[k])>>8);
		}
		if(alfam==0)alfam=1;
		km = -((t<<8)/alfam);
		for(k=1; k<=m-1; k++){
			b[k] = a[m-k];
		}
		for(k=1; k<=m-1; k++){
			a[k] = a[k] + ((km*b[k])>>8);
		}
		a[m] = km;
		alfam = (alfam*((1<<8) - ((a[m]*a[m])>>8)))>>8;
	}
	alfa = alfam;
	for(i=0; i0; i--){
		out_buf[i-1] = 0;
	}
}

//// ADC割り込み処理(約16kHz)
void _ISRFAST _ADCInterrupt(void)
{
	long int tone;
	fractional SigIn;
	long int out;
	int d_out;
	int i;
	int on;
		
	IFS0bits.ADIF = 0;
	
	//音程生成
	s_cnt++;
	if(s_cnt==16){
		s_cnt = 0;
		tone=1<<7;
	}else{
		tone=0;
	}
	
	//AD input
	in_buf[ix_buf] = (long int)(ReadADC10(0)>>2)-128;
	if(in_buf[ix_buf]<32 && in_buf[ix_buf]>-32){
		in_buf[ix_buf]=0;
		zero_cnt++;
		//sound = 0;
	}else{
		sound = 1;
		zero_cnt = 0;
	}		
	if(zero_cnt>10){sound = 0;}
	if(sound==0){tone = 0;}
	ix_buf++;
	if(ix_buf>=BUF_LEN){
		ix_buf = 0;
	}	
	
	
	//合成フィルタ
	out = -(	((lpc[0] * out_buf[0])>>8)
					+ ((lpc[1] * out_buf[1])>>8)
					+ ((lpc[2] * out_buf[2])>>8)
					+ ((lpc[3] * out_buf[3])>>8)
					)
					+ tone;
	for(i=LPC_ORDER; i>0; i--){
		out_buf[i] = out_buf[i-1];
	}
	out_buf[0] = out;

	//出力処理
	d_out = 0x7000 | ((0x8000 + (out<<7))>>4);
	LATEbits.LATE0 = 0;  //CS=0
  	for(i=0; i<16; i++){
    	if(((d_out << i) & 0x8000) != 0){
      		LATEbits.LATE2 = 1;  //SDI=1
    	}else{
      		LATEbits.LATE2 = 0;  //SDI=0
    	}
    	LATEbits.LATE1 = 1;  //SCK=1
    	LATEbits.LATE1 = 0;  //SCK=0
  	}
  	LATEbits.LATE0 = 1;  //CS=1
  	LATEbits.LATE3 = 0;  //LDAC=0
  	LATEbits.LATE3 = 1;  //LDAC=0
}

//main-----------------------------------------------------------------------
int main(void)
{
	int i,j;
	int data;
	
//Initialize
	LATE = 0x0000;	//

// Setup Port
	TRISB = 0x01;	//AN0 input
	TRISE = 0x00;	//all output
	SRbits.IPL=4;	//Set CPU priority Set core priority level to 4

// Setup ADC10		
	OpenADC10(ValueADCON1, ValueADCON2, ValueADCON3, ValueADPCFG, ValueADCSSL);
	SetChanADC10(Channel0);
	ConfigIntADC10(ADC_INT_PRI_7 & ADC_INT_ENABLE);

// タイマ1設定　サンプリング周期　4/256/2kHz = (7.37MHz*16/4)/256/3684
	OpenTimer1(T1_ON & T1_GATE_OFF & T1_PS_1_256 & T1_SOURCE_INT,3684*2-1);
	IPC0bits.T1IP = 5;
	IFS0bits.T1IF = 0;
	IEC0bits.T1IE = 1;

// タイマ３設定　サンプリング周期　4kHz = (7.37MHz*16/4)/1842
	OpenTimer3(T3_ON & T3_GATE_OFF & T3_PS_1_1 & T3_SOURCE_INT,1842*4-1);

// init mcp4922
	LATEbits.LATE0 = 1;	//CS
	LATEbits.LATE1 = 0;	//SCK
	LATEbits.LATE2 = 0;	//SDI
	LATEbits.LATE3 = 1;	//LDAC
	
//Idle Loop
	while (1){};
}