AT43USB325E-AU Atmel, AT43USB325E-AU Datasheet - Page 56

• Manufacturer Part Number: AT43USB325E-AU
• Description: IC USB KEYBOARD CTRLR 64LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB325E-AU

• Applications: Keyboard Controller
• Core Processor: AVR
• Program Memory Type: SRAM (16 kB)
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: SPI, 3-Wire Serial
• Number Of I /o: 42
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7.1
7.1.1
7.1.2
7.1.3
56
Port A
AT43USB325
Port A Data Register – PORTA
Port A Data Direction Register – DDRA
Port A Input Pins Address – PINA
Port A is an 8-bit bi-directional I/O port with open drain outputs and controlled slew rate. It is
designed for use as the column driver in a keyboard controller. The Port A output buffers can
sink or source 4 mA.
Three I/O memory address locations are allocated for the Port A, one each for the Data Register
PORTA, $1B($3B), Data Direction Register (DDRA), $1A($3A) and the Port A Input Pins (PINA)
$19($39). The Port A Input Pins address is read only, while the Data Register and the Data
Direction Register are read/write.
The Port A Input Pins address (PINA) is not a register, and this address enables access to the
physical value on each Port A pin. When reading PORTA the Port A Data Latch is read, and
when reading PINA, the logical values present on the pins are read.
Initial Value
Read/Write
Initial Value
Read/Write
Initial Value
Read/Write
$1B ($3B)
$1A ($3A)
$19 ($39)
Bit
Bit
Bit
PORTA7
PINA7
DDA7
R/W
R/W
N/A
R
7
0
7
0
7
PORTA6
PINA6
DDA6
R/W
R/W
N/A
6
0
R
6
0
6
PORTA5
PINA5
DDA5
R/W
R/W
N/A
5
0
5
0
R
5
PORTA4
DDA4
PINA4
R/W
R/W
N/A
4
0
4
0
4
R
PORTA3
DDA3
PINA3
R/W
R/W
N/A
3
0
R
3
0
3
PORTA2
DDA2
PINA2
R/W
R/W
N/A
2
0
2
0
R
2
PORTA1
DDA1
PINA1
R/W
R/W
N/A
1
0
1
0
R
1
PORTA0
DDA0
PINA0
R/W
R/W
N/A
0
0
R
0
0
0
3355C–USB–4/05
PORTA
DDRA
PINA