ATmega 328P Internal Temperature Sensor on ADC8

gistfile1.txt

; Initialise A/D multiplex register for internal temp. sensor (ADC8)
; Use internal (1.1V) as reference voltage and left-adjust
ADC_TempSensor_Init:
	ldi		r17, (1<<REFS1) | (1<<REFS0) | (1<<MUX3) | (1<<ADLAR)
	sts		ADMUX, r17						; out of range for OUT, using STS instead
	ret

; Reads ADCL into r21 and ADCH into r22
ADC_TempSensor_Read:
	; Enable ADC with a clock division factor of 128 (125 kHz)
	ldi		r17, (1<<ADEN) | (1<<ADSC) | (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0)
	sts		ADCSRA, r17

	ADC_Wait_TempSensor:
		lds		r17, ADCSRA
		sbrc	r17, ADSC
		rjmp	ADC_Wait_TempSensor
		lds		r21, ADCL
		lds		r22, ADCH
	ret