AT43USB320A_04 ATMEL [ATMEL Corporation], AT43USB320A_04 Datasheet - Page 68

• Manufacturer Part Number: AT43USB320A_04
• Description: Full-speed USB Microcontroller with an Embedded Hub
• Manufacturer: ATMEL [ATMEL Corporation]

Port D
68
AT43USB320A
Port D is an 8-bit bi-directional I/O port. Its output buffers can sink or source 2 mA.
Three I/O memory address locations are allocated for the Port D, one each for the Data Regis-
ter - PORTD, $12($32), Data Direction Register (DDRD), $11($31) and the Port D Input Pins
(PIND), $10($30). The Port D Input Pins’ address is read only, while the Data Register and the
Data Direction Register are read/write.
The port pins have no selectable pull-up resistors.
Some Port D pins have alternate functions as shown in Table 27.
Table 27. Port D Alternate Functions
When the pins are used for the alternate function the DDRD and PORTD register has to be set
according to the alternate function description.
Port D Data Register – PORTD
Port D Data Direction Register – DDRD
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.
Read/Write
Initial Value
Read/Write
Initial Value
Read/Write
Initial Value
$11 ($31)
$10 ($30)
$12 ($32)
Bit
Bit
Bit
Port Pin
PD0
PD1
PD2
PD3
PD5
PORTD7
PIND7
DDD7
R/W
R/W
N/A
7
0
7
0
R
7
PORTD6
DDD6
PIND6
R/W
R/W
N/A
6
0
6
0
R
6
Alternate Function
RXD (UART Input Line)
TXD (UART Output Line)
INT0, External Interrupt 0
INT1, External Interrupt 1
OC1A Timer/Counter1 Output Compare A
PORTD5
DDD5
PIND5
R/W
R/W
N/A
5
0
5
0
R
5
PORTD4
PIND4
DDD4
R/W
R/W
N/A
R
4
0
4
0
4
PORTD3
PIND3
DDD3
R/W
R/W
N/A
R
3
0
3
0
3
PORTD2
PIND2
DDD2
R/W
R/W
N/A
2
R
2
0
2
0
PORTD1
PIND1
DDD1
R/W
R/W
N/A
R
1
1
0
1
0
PORTD0
PIND0
DDD0
R/W
R/W
N/A
0
0
0
R
0
0
1443E–USB–4/04
PORTD
DDRD
PIND