;***************************************************************************
;ADC Initialisation
;***************************************************************************
;  REFS0:  0(default)=Vcc reference,  1=internal 1.1V reference
;  ADLAR:  0(default)=right adjusted,  1=left adjusted (result in ADCL/H).

;  MUX1  MUX0  Single Ended Input
;  0     0     ADC0(default)
;  0     1     ADC1
;  1     0     ADC2
;  1     1     ADC3
;  Note: if ADC is disabled and ACME bit is set in ADCSRB, MUX is used to 
;  select comparator negative input.

    ldi    tempa,(0<<REFS0)|(0<<ADLAR)|(0<<MUX1)|(0<<MUX0)  
    out    ADMUX,tempa

;  ACME:  0=AIN1 to comparator negative input (default),
;         1=MUX output to neg input if ADEN=0, otherwise AIN1 to neg i/p.

;  ADTS2  ADTS1  ADTS0  ADC Trigger Source
;  0      0      0      Free Running mode (default)
;  0      0      1      Analog Comparator
;  0      1      0      External Interrupt Request 0
;  0      1      1      Timer/Counter Compare Match A
;  1      0      0      Timer/Counter Overflow
;  1      0      1      Timer/Counter Compare Match B
;  1      1      0      Pin Change Interrupt Request

    ldi    tempa,(0<<ACME)|(0<<ADTS2)|(0<<ADTS1)|(0<<ADTS0)  
    out    ADCSRB,tempa

;  ADEN:  0(default)=ADC off,  1=ADC on
;  ADSC:  0(default)=no effect,  1=start conversion (see note)
;  ADATE: 0(default)=auto trigger off,  1=auto trigger enabled
;  ADIE:  0(default)=interrupt disabled,  1=interrupt enabled

;  ADPS2  ADPS1  ADPS0  Clock Prescaler Division Factor
;  0      0      0      2 (default)
;  0      0      1      2
;  0      1      0      4
;  0      1      1      8
;  1      0      0      16
;  1      0      1      32
;  1      1      0      64
;  1      1      1      128
;  Note: ADC prescaler must be set to give 50-200kHz ADC clock

    ldi    tempa,(0<<ADEN)|(0<<ADSC)|(0<<ADATE)|(0<<ADIE)|(0<<ADPS2)|(0<<ADPS1)|(0<<ADPS0)  
    out    ADCSRA,tempa

;  Note:ADSC bit is not normally set as part of initialisation, unless
;  ADC is enabled and free running mode is selected.