Datasheet
148
ATmega323(L)
1457E–11/01
The Port D Data Register –
PORTD
The Port D Data Direction
Register – DDRD
The Port D Input Pins Address
– PIND
The Port D Input Pins address
– PIND – is not a register, and this address enables
access to the physical value on each Port D pin. When reading PORTD, the Port D Data
Latch is read, and when reading PIND, the logical values present on the pins are read.
Port D As General Digital I/O PDn, General I/O pin: The DDDn bit in the DDRD register selects the direction of this
pin. If DDDn is set (one), PDn is configured as an output pin. If DDDn is cleared (zero),
PDn is configured as an input pin. If PDn is set (one) when configured as an input pin
the MOS pull up resistor is activated. To switch the pull up resistor off the PDn has to be
cleared (zero), the pin has to be configured as an output pin, or the PUD bit has to be
set. The Port D pins are tri-stated when a reset condition becomes active, even if the
clock is not running.
Note: n: 7,6…0, pin number.
Alternate Functions of Port D • OC2 - Port D, Bit 7
OC2, Timer/Counter2 output compare match output: The PD7 pin can serve as an
external output for the Timer/Counter2 output compare. The pin has to be configured as
an output (DDD7 set (one)) to serve this function. See the timer description on how to
enable this function. The OC2 pin is also the output pin for the PWM mode timer
function.
Bit 76543210
$12 ($32)
PORTD7 PORTD6 PORTD5 PORTD4 PORTD3 PORTD2 PORTD1 PORTD0 PORTD
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Val-
ue
00000000
Bit 76543210
$11 ($31)
DDD7 DDD6 DDD5 DDD4 DDD3 DDD2 DDD1 DDD0 DDRD
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value00000000
Bit 76543210
$10 ($30)
PIND7 PIND6 PIND5 PIND4 PIND3 PIND2 PIND1 PIND0 PIND
Read/WriteRRRRRRRR
Initial Value N/A N/A N/A N/A N/A N/A N/A N/A
Table 54. DDDn Effects on Port D Pins
DDDn PORTDn
PUD
(in SFIOR) I/O Pull Up Comment
0 0 X Input No Tri-state (Hi-Z)
0 1 0 Input Yes
PDn will Source Current if Ext. Pulled
Low.
0 1 1 Input No Tri-state (Hi-Z)
1 0 X Output No Push-pull Zero Output
1 1 X Output No Push-pull One Output