여러개의 ADC 사용할때 주의 사항!!!

여러개의 ADC를 사용할때에는 MUX를 미리 설정하고 그다음에 함수를 불러들려서 값을 

읽어야 한다 !!.

ex)

#include <avr/io.h>

#include <avr/interrupt.h>

#include <stdio.h>

#include <util/delay.h>

#define  F_CPU               16000000L

#define  TRUE 1

#define  FALSE 0

void ADC_START(unsigned int *g_adcData0)

{

unsigned int ADC_DataH=0,ADC_DataL = 0;

//cCount++;

ADMUX = 0x00;

ADCSRA = 0xc3;

*g_adcData0 = 0;

while(!(ADCSRA & (1<<ADIF)));

ADC_DataL = ADCL & 0xff;

ADC_DataH = ADCH & 0x03;

//printf("L : %d\n",ADC_DataL);

*g_adcData0 = (ADC_DataH <<8) | ADC_DataL;

//*g_adcData = (*g_adcData >> 6);

//*g_adcData = ADC_DataH;

    ADMUX = (1<<MUX2);

ADCSRA |= (1<<4);

}

void ADC_START1(unsigned int *g_adcData1)

{

unsigned int ADC_DataH=0,ADC_DataL = 0;

ADCSRA = 0xc3;

*g_adcData1 = 0;

while(!(ADCSRA & (1<<ADIF)));

ADC_DataL = ADCL & 0xff;

ADC_DataH = ADCH & 0x03;

*g_adcData1= (ADC_DataH <<8) | ADC_DataL;

ADMUX = (1<<MUX1);

ADCSRA |= (1<<4);

}

int ADC_START2(unsigned int *g_adcData2)

{

unsigned int ADC_DataH=0,ADC_DataL = 0;

ADCSRA = 0xc3;

*g_adcData2 = 0;

while(!(ADCSRA & (1<<ADIF)));

ADC_DataL = ADCL & 0xff;

ADC_DataH = ADCH & 0x03;

*g_adcData2 = (ADC_DataH <<8) | ADC_DataL;

ADMUX = (1<<MUX1)|(1<<MUX0);

ADCSRA |= (1<<4);

}

int ADC_START3(unsigned int *g_adcData3)

{

unsigned int ADC_DataH=0,ADC_DataL = 0;

ADCSRA = 0xc3;

*g_adcData3 = 0;

while(!(ADCSRA & (1<<ADIF)));

ADC_DataL = ADCL & 0xff;

ADC_DataH = ADCH & 0x03;

*g_adcData3 = (ADC_DataH <<8) | ADC_DataL;

ADMUX = 0x00;

ADCSRA |= (1<<4);

}

int INIT_PIN()

{

DDRF = 0x00;

DDRE = 0x02;

DDRB = 0xff;

DDRD = 0x08;

PORTF = 0x00;

PORTE = 0x02;

PORTD = 0x08;

return TRUE;

}

int INIT_USART0(int baud0)

{

int ubrr0 = F_CPU/16/baud0-1; // baud rate setting

UCSR0A = 0x00;

UCSR0B = 0x18;

UCSR0C = 0x06;

UBRR0H = (unsigned char)(ubrr0 >> 8); //int value  shift 8 right 

UBRR0L = (unsigned char)ubrr0; //low data setting

return TRUE;

}

int INIT_USART1(int baud1)

{

int ubrr1 = F_CPU/16/baud1-1; // baud rate setting

UCSR1A = 0x00;

UCSR1B = 0x18;

UCSR1C = 0x06;

UBRR1H = (unsigned char)(ubrr1 >> 8); //int value  shift 8 right 

UBRR1L = (unsigned char)ubrr1; //low data setting

return TRUE;

}

int USART0_Putch(char Usdata0)

{

while(!(UCSR0A & (1<<5)));

UDR0 = Usdata0;

return TRUE;

}

int USART1_Putch(unsigned char Usdata1, FILE *stream )

{

if( Usdata1 == '\n' ) USART1_Putch( '\r',stream);

while(!(UCSR1A & (1<<5)));

UDR1 = Usdata1;

return TRUE;

}

int Sleep_mode(void)

{

MCUCR = (1<<5) | (1<SM0);

return TRUE;

}

int main()

{

FILE usart1 = FDEV_SETUP_STREAM( USART1_Putch,NULL,_FDEV_SETUP_RW );

  stdin = stdout = &usart1;

  int i = 0;

unsigned int ADC0_Data=0,ADC1_Data = 0, ADC2_Data = 0, ADC3_Data = 0; 

if(INIT_USART0(9600)) printf("USART SET OK\n"); 

if(INIT_USART1(9600)) printf("USART SET OK\n"); 

if(INIT_PIN()) printf("PIN SET OK\n");

//if(INIT_INTERRUPT()) printf("INTERRUPT SET OK\n");

if(Sleep_mode()) printf("Sleep Mode SET OK\n");

for(;;)

{

ADC_START(&ADC0_Data);

_delay_us(10);

ADC_START1(&ADC1_Data);

_delay_us(10);

ADC_START2(&ADC2_Data);

_delay_us(10);

ADC_START3(&ADC3_Data);

_delay_us(10);

printf("ADC : %d , ADC1 :%d , ADC2 : %d, ADC3 : %d\n",ADC0_Data,ADC1_Data,ADC2_Data,ADC3_Data);

_delay_ms(100);

}

return 0;

}

사이에 딜레이를 주는 이유는 ADC를 한번하고 다음 ADC까지의 25주기의 클럭 주기가 필요하기
때문이다!!.