Datasheet

223
8021G–AVR–03/11
ATmega329P/3290P
• Differential Non-linearity (DNL): The maximum deviation of the actual code width (the interval
between two adjacent transitions) from the ideal code width (1 LSB). Ideal value: 0 LSB.
Figure 22-13. Differential Non-linearity (DNL)
• Quantization Error: Due to the quantization of the input voltage into a finite number of codes, a
range of input voltages (1 LSB wide) will code to the same value. Always ± 0.5 LSB.
• Absolute Accuracy: The maximum deviation of an actual (unadjusted) transition compared to
an ideal transition for any code. This is the compound effect of offset, gain error, differential
error, non-linearity, and quantization error. Ideal value: ± 0.5 LSB.
22.8 ADC Conversion Result
After the conversion is complete (ADIF is high), the conversion result can be found in the ADC
Result Registers (ADCL, ADCH).
For single ended conversion, the result is
where V
IN
is the voltage on the selected input pin and V
REF
the selected voltage reference (see
Table 3 on page 225 and Table 22-3 on page 226). 0x000 represents analog ground, and 0x3FF
represents the selected reference voltage minus one LSB.
Output Code
0x3FF
0x000
0
V
REF
Input Voltage
DNL
1 LSB
ADC
V
IN
1024⋅
V
REF
--------------------------=
ADC
V
POS
V
NEG
–()512⋅
V
REF
---------------------------------------------------- -=