AT43USB355M-AC ATMEL [ATMEL Corporation], AT43USB355M-AC Datasheet - Page 68

• Manufacturer Part Number: AT43USB355M-AC
• Description: Full-speed USB Microcontroller with Embedded Hub, ADC and PWM
• Manufacturer: ATMEL [ATMEL Corporation]

Port B
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AT43USB355
Port B is an 8-bit bi-directional I/O port. The Port B output buffers can sink or source 2 mA.
Three I/O memory address locations are allocated for the Port B, one each for the Data Regis-
ter - 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.
All port pins have individually selectable pull-up resistors. When pins PB0 to PB7 are used as
inputs and are externally pulled low, they will source current if the internal pull-up resistors are
activated
The Port B pins with alternate functions are shown in the following table:
Table 25. Port B Pins Alternate Functions
When the pins are used for the alternate function the DDRB and PORTB register has to be set
according to the alternate function description.
Port Pin
PB0
PB1
PB4
PB5
PB6
PB7
Alternate Functions
T0 (Timer/Counter 0 External Counter Input)
T1 (Timer/Counter 1 External Counter Input)
SS (SPI Slave Select Input)
MOSI (SPI Bus Master Output/Slave Input)
MISO (SPI Bus Master Input/Slave Output)
SCK (SPI Bus Serial Clock)
2603G–USB–04/06