Quellcode

i2c_master_init();
	
while (1) {
	// Temperatur holen
	i2c_master_start();
	i2c_master_read(0);
	temp = i2c_master_read(1);
	i2c_master_stop();
	temp >>= 1;
	[...]

Quellcode

#define I2C_DDR			DDRC					// Register für die I2C Kommunikation
#define I2C_DDR_REG_BIT	DDC3						//
#define I2C_PORT		PORTC					// I2C Port definition

#define SCL				PC4
#define SDA				PC3

#define SDA_LESE_PIN 	PINC
#define SDA_LESE_BIT 	SDA

Quellcode

i2c_master_start();
i2c_master_write(TEMP_ADDR); // TEMP_ADDR = 0b10010001
temp = i2c_master_read(0);
temp2 = i2c_master_read(1);
i2c_master_stop();

Quellcode

O 5V
|
R 2,5kOhm
|
|-- 10mV/K
|
LM335
|
O GND

Quellcode

// ADC gemittelt auslesen
uint16_t readADC()
{
	uint16_t erg;
	uint8_t adlow, adhigh, tmp = 0, tmp1 = 0, tmp2 = 0, tmp3 = 0, messungen = 0, quit = 0;
	
	while (quit != 1) {
		ADCSRA |= (1 << ADSC); // ADC starten
		while (ADCSRA & (1 << ADSC)); // Warten, bis beendet
		
		adlow = ADCL;
		adhigh = ADCH;
		
		asm volatile ("add %[tmp1], %[adlow]" : [tmp1] "+r" (tmp1), [adlow] "+r" (adlow));
		asm volatile ("adc %[tmp2], %[adhigh]" : [tmp2] "+r" (tmp2), [adhigh] "+r" (adhigh));
		asm volatile ("adc %[tmp3], %[tmp1]" : [tmp3] "+r" (tmp3), [tmp1] "+r" (tmp1));
		
		messungen++;
		if (messungen == 255) // bei 256 Durchläufen
			quit = 1;		  // abbrechen
	}
	
	if (tmp1 > 128) { // wenn größer als 128 muss aufgerundet werden
		// Die folgenden beiden Zeilen erzeugen einen Fehler, deshalb erst mal weg gelassen
		//asm volatile ("subi %[tmp2], low(-1)" : [tmp2] "+r" (tmp2));
		//asm volatile ("sbci %[tmp3], high(-1)" : [tmp3] "+r" (tmp3));
	}
	
	adlow = tmp2;
	adhigh = tmp3;
	
	return adlow | (adhigh << 8);
}

Quellcode

uint16_t readADC()
{
	uint32_t sum = 0;
	uint16_t i = 0;
	uint8_t adlow, adhigh;
	
	for (i = 0; i <= 255; i++) {
		ADCSRA |= (1 << ADSC); // ADC starten
		while (ADCSRA & (1 << ADSC)); // Warten, bis beendet
		
		adlow = ADCL;
		adhigh = ADCH;
		
		sum += ADCL + (ADCH << 8);
	}
	
	return (uint16_t) (sum >> 8);
}