Atmel ATmega48A Manual page 260

24.6.3 ADC Accuracy Definitions
8271D–AVR–05/11
ATmega48A/PA/88A/PA/168A/PA/328/P
and ADC5) will only affect the conversion on ADC4 and ADC5 and not the other ADC
channels.
Figure 24-9. ADC Power Connections
An n-bit single-ended ADC converts a voltage linearly between GND and V
(LSBs). The lowest code is read as 0, and the highest code is read as 2
Several parameters describe the deviation from the ideal behavior:
• Offset: The deviation of the first transition (0x000 to 0x001) compared to the ideal transition (at
0.5 LSB). Ideal value: 0 LSB.
PC1 (ADC1)
PC0 (ADC0)
ADC7
GND
AREF
ADC6
AVCC
PB5
in 2
REF
n
-1.
n
steps
260