Single-ended Conversion Range

Single-ended conversion feeds the input channel directly to the conversion circuitry, as shown in the figure Figure 1 (A) above. The 10-bit ADC of the AVR therefore converts continuous input voltages from GND to V_REF to discrete output values from 0 to 1023.

Any applied input voltage greater than the reference voltage V_REF will return the maximum value (1023 using 10-bit ADC), and any negative input voltage will return 0.