resistors are activated. The Port D pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
The various special features of Port D are elaborated in
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.
4
ATmega48/88/168
2545R–AVR–07/09
ATMEL [ ATMEL CORPORATION ]
