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• Are all CONTINUOUS time signals ANALOG ?
• All continuous time signals are analog but all analog signals are not continuous time
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• The ADC converts an analog input voltage to a 10-bit digital value through successive approximation.
• The minimum value represents GND and the maximum value represents the voltage on the AREF pin minus 1 LSB
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• What's wrong with totally analog ?• Ans – Two arrows in a Quiver is always
better than one
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A digital signal is superior to an analogsignal because it is more robust to noiseand can easily be recovered, correctedand amplified. For this reason, thetendency today is to change an analogsignal to digital data
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ReadADCX() {
ADMUX=0x4X;ADCSRA=0x86;SETBIT(ADCSRA,BIT(6));
while(!(ADCSRA & (1<<ADIF)));s=ADC;
return(s);}
NOTE: X can take value from 0 to 7
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• ADMUX = 0x4X
• Let x = 1
⇒ ADMUX = 0x41 ⇒ ADMUX = 01000001
0 1 0 0 0 0 0 1
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The ADLAR bit affects the presentation of the ADC conversion result in the ADC Data Register.
• ADLAR = 0 ⇒ LEFT ADJUST
• ADLAR = 1 ⇒ RIGHT ADJUST
0 1 0 0 0 0 0 1
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ReadADCX() {
ADMUX=0x4X; // DONEADCSRA=0x86;SETBIT(ADCSRA,BIT(6));
while(!(ADCSRA & (1<<ADIF)));s=ADC;
return(s);}
NOTE: X can take value from 0 to 7
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• ADCSRA = 0x86
• Let x = 1
⇒ ADCSRA = 0x41 ⇒ ADCSRA = 10000110
1 0 0 0 0 1 1 0
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• BIT 7
• ADEN ⇒ ADC Enable bit
• ADEN = 1 ⇒ Enable ADC
• ADEN = 0 ⇒ Disable ADC
1 0 0 0 0 1 1 0
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• BIT 6
• ADSC - Write this bit to one to start each conversion
1 0 0 0 0 1 1 0
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• BIT 4
• ADIF - This bit is set when an ADC conversion completes
1 0 0 0 0 1 1 0
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ReadADCX() {
ADMUX=0x4X; // DONEADCSRA=0x86; // DONESETBIT(ADCSRA,BIT(6)); // DONE
while(!(ADCSRA & (1<<ADIF)));s=ADC;
return(s);}
NOTE: X can take value from 0 to 7
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