AT43USB325E-AU Atmel, AT43USB325E-AU Datasheet - Page 57

• 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

7.2
7.2.1
7.2.2
7.2.3
3355C–USB–4/05
Port B
Port B Data Register – PORTB
Port B Data Direction Register – DDRB
Port B Input Pins Address – PINB
Port B 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 B output buffers can
sink or source 4 mA.
Three I/O memory address locations are allocated for the Port B, one each for the Data Register
- PORTB, $18($38), Data Direction Register (DDRB), $17($37) and the Port B Input Pins
(PINB), $16($36). The Port B Input Pins address is read only, while the Data Register and the
Data Direction Register are read/write.
The Port B Input Pins address (PINB) is not a register, and this address enables access to the
physical value on each Port B pin. When reading PORTB, the Port B Data Latch is read, and
when reading PINB, the logical values present on the pins are read.
Initial Value
Initial Value
Read/Write
Initial Value
Read/Write
Read/Write
$18 ($38)
$17 ($37)
$16 ($36)
Bit
Bit
Bit
PORTB7
PINB7
DDB7
R/W
R/W
N/A
R
7
0
7
7
0
PORTB6
PINB6
DDB6
R/W
R/W
N/A
R
6
0
6
6
0
PORTB5
PINB5
DDB5
R/W
R/W
N/A
R
5
0
5
5
0
PORTB4
PINB4
DDB4
R/W
R/W
N/A
R
4
4
0
4
0
PORTB3
PINB3
DDB3
R/W
R/W
N/A
3
R
3
0
3
0
PORTB2
PINB2
DDB2
R/W
N/A
R/W
R
2
2
0
2
0
PORTB1
AT43USB325
PINB1
DDB1
R/W
R/W
N/A
R
1
1
0
1
0
PORTB0
PINB0
DDB0
R/W
N/A
R/W
R
0
0
0
0
0
PORTB
DDRB
PINB
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