User manual

4
8025I–AVR–02/09
ATmega48P/88P/168P/328P
The various special features of Port D are elaborated in ”Alternate Functions of Port D” on page
88.
1.1.7 AV
CC
AV
CC
is the supply voltage pin for the A/D Converter, PC3:0, and ADC7:6. It should be externally
connected to V
CC
, even if the ADC is not used. If the ADC is used, it should be connected to V
CC
through a low-pass filter. Note that PC6..4 use digital supply voltage, V
CC
.
1.1.8 AREF
AREF is the analog reference pin for the A/D Converter.
1.1.9 ADC7:6 (TQFP and QFN/MLF Package Only)
In the TQFP and QFN/MLF package, ADC7:6 serve as analog inputs to the A/D converter.
These pins are powered from the analog supply and serve as 10-bit ADC channels.
2. Overview
The ATmega48P/88P/168P/328P is a low-power CMOS 8-bit microcontroller based on the AVR
enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the
ATmega48P/88P/168P/328P achieves throughputs approaching 1 MIPS per MHz allowing the
system designer to optimize power consumption versus processing speed.