stm32f103c8 stabil adc

[bicer]

Merhaba arkadaşlar. stm32f103c8 ile ntc termometre yapıyorum (hal kütüphanesi kullanmadan registerlar üzerinden yazarak).Kod bu haliyle çalışıyor fakat tam stabil degil son basamaktaki deger sürekli oynuyor adc yi nasıl daha stabil hale getirebilirim?

#include "stm32f10x.h"                  // Device header
#include "math.h"
float sicaklik = 0;
char analog[10];
char analog2[10];
int isi;
int a=0;
void int2char(int num, char str[])
{
  char lstr[30];
   int cnt = 0;
  int div = 10;
  int j = 0;

	
	
while( num >= div)
{
	lstr[cnt] = num % div + 0x30;
	num /= 10;
	cnt++;
}
	lstr[cnt] = num + 0x30;
for(j= cnt ; j >=0;j--)
{
	str[cnt-j] = lstr[j];
}
   
   
}

void DelayUs(unsigned long t)
{
	for(;t>0;t--)
		{
		 SysTick->LOAD = 72;
	   SysTick->VAL = 0;
	   while((SysTick->CTRL & 0x00010000) == 0);
		}
}


void lcd_cmd(unsigned char data)
{
	//pin_output(0,11);
	GPIOA->ODR &=~0x100;//lcd_rs(LOW);
	GPIOA->ODR &=~0x200;//lcd_rw(LOW);
	DelayUs(10);
	GPIOA->ODR |=0x400;//lcd_e(HIGH);
	DelayUs(5);
	GPIOA->ODR &= 0xff0f;
	GPIOA->ODR |= (data & 0x00f0);
	DelayUs(10);
	GPIOA->ODR &=~0x400;//lcd_e(LOW);
	
	DelayUs(20);
	
	GPIOA->ODR |=0x400;//lcd_e(HIGH);
	DelayUs(5);
	GPIOA->ODR &= 0xff0f;
	GPIOA->ODR |= ((data << 4) & 0x00f0);
	DelayUs(10);
	GPIOA->ODR &=~0x400;//lcd_e(LOW);
}

void lcd_data(unsigned char data)
{
	//pin_output(4,7);
	GPIOA->ODR |=0x100;//lcd_rs(HIGH);
	GPIOA->ODR &=~0x200;//lcd_rw(LOW);
	DelayUs(10);
	GPIOA->ODR |=0x400;//lcd_e(HIGH);
	DelayUs(5);
	GPIOA->ODR &= 0xff0f;
	GPIOA->ODR |= (data & 0x00f0);
	DelayUs(10);
	GPIOA->ODR &=~0x400;//lcd_e(LOW);
	
	DelayUs(20);
	
	GPIOA->ODR |=0x400;//lcd_e(HIGH)
	DelayUs(5);
	GPIOA->ODR &= 0xff0f;
	GPIOA->ODR |= ((data << 4) & 0x00f0);
	DelayUs(10);
	GPIOA->ODR &=~0x400;//lcd_e(LOW)
}

void lcd_send( char str[])
{
	int i = 0;
		while(str[i])
		{
			lcd_data(str[i]);
			i++;
			DelayUs(100);
		}

}


void lcd_msg(unsigned char line_1_2, unsigned char pos_0_16, char msg[])
{
	short pos = 0;
	if(line_1_2==1)
	{
		pos = 0;
	}
	else if(line_1_2==2)
	{
		pos = 0x40;
	}
	lcd_cmd(0x80 +pos + pos_0_16);
	DelayUs(100);
	lcd_send(msg);
}



int main(void)
{
	// initialize the delay function (Must initialize)
	SysTick->CTRL = 0;
	SysTick->LOAD = 0x00FFFFFF;
	SysTick->VAL = 0;
	SysTick->CTRL = 5;
	
	
	//pin_output(4,11);
	RCC->APB2ENR = 0x04; /// port a aktif
	GPIOA->CRL   = 0x33330000; /// pin 3 ü çikis olarak ayarla
	GPIOA->CRH   = 0x00003333; /// pin 3 ü çikis olarak ayarla
	GPIOA->CRL &= 0xFFFFF0FF; /// A3 pini resetlendi
	GPIOA->CRL |= 0x00000000; //a2 sifir
	DelayUs(20000);
	GPIOA->ODR |=0x100;//lcd_rs(LOW);
	GPIOA->ODR |=0x200;//lcd_rw(LOW);
	DelayUs(10);
	GPIOA->ODR |=0x400;//lcd_e(HIGH);
	DelayUs(5);
	GPIOA->ODR &= 0xff0f;
	GPIOA->ODR |= 0x30; // 8 bit communication mode 
	DelayUs(10);
	GPIOA->ODR &=~0x400;//lcd_e(LOW);
	
	DelayUs(20000);
	
	
	GPIOA->ODR &=~0x100;//lcd_rs(LOW);
	GPIOA->ODR &=~0x200;//lcd_rw(LOW);
	DelayUs(10);
	GPIOA->ODR |=0x400;//lcd_e(HIGH);
	DelayUs(5);
	GPIOA->ODR &= 0xff0f;
	GPIOA->ODR |= 0x20; // 4 bit communication mode 
	DelayUs(10);
	GPIOA->ODR &=~0x400;//lcd_e(LOW);
	
	
	lcd_cmd(0x2C); // 4 bit communication mode / 2 lines
	DelayUs(5000);
	lcd_cmd(0x0C); // Display ON
	DelayUs(5000);
	lcd_cmd(0x01); // Clear Display
	DelayUs(5000);
	lcd_cmd(0x02); // Get back to initial address
	DelayUs(5000);
	
		lcd_msg(1, 0,"Sicaklik(C)");
		RCC->APB2ENR |= 0x201; //ADC 1 interface clock enable
		ADC1->SQR3 = 2;  //düzenli sirayla ilk dönüsüm  
		ADC1->SQR1 &= ~(0xf << 20);//adc kanal dizisi uzunlugu			
    ADC1->SMPR2 |= (0x1);	//7.5 döngü
    //12mhz: 7.5+12.5 =20 hz ->3.3us(mikro Saniye) 
    ADC1->CR2 &= ~(1 << 11); // right alignment		
    ADC1->CR2 |= 2|1; //adc açik ve surekli
    ADC1->CR2 |= (1<<3);//kalibrasyon reset
    ADC1->CR2 |= (1<<2);// kalibrasyon	
    ADC1->CR2 |=1; //adc açik	
	while(1)
	{
  sicaklik = log(((40950000 / ADC1->DR) - 10000));
  sicaklik = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * sicaklik * sicaklik)) * sicaklik);
  isi = (sicaklik - 273.15)*100; 
	 int2char(isi,analog);
	 lcd_msg(2, 2,analog);
		if(isi<1000)
		{
		 a=3;	
		}
		else if(isi<10000)
		{
     a=4;
		}
    else
		{
     a=5;
		}			
	 isi=isi%100;
	 int2char(isi,analog2);
	 lcd_msg(2, a,".");
	 lcd_msg(2, a+1,analog2);
	 lcd_msg(2, a+3,"     ");
	 DelayUs(250000);
	}
	
}