Read/Write
Initial Value
R/W
0
R
0
R
0
R/W
0
R
0
R
0
R/W
0
R/W
0
• Bit 4 – PUD: Pull-up Disable
When this bit is written to one, the pull-ups in the I/O ports are disabled even if the DDxn and
PORTxn Registers are configured to enable the pull-ups ({DDxn, PORTxn} = 0b01). See “Con-
figuring the Pin” on page 68 for more details about this feature.
11.3.2
Alternate Functions of Port B
The Port B pins with alternate functions are shown in Table 11-3.
Table 11-3. Port B Pins Alternate Functions
Port Pin
Alternate Functions
OC0A/OC1C/PCINT7 (Output Compare and PWM Output A for Timer/Counter0, Output
Compare and PWM Output C for Timer/Counter1 or Pin Change Interrupt 7)
PB7
PB6
PB5
PB4
PCINT6 (Pin Change Interrupt 6)
PCINT5 (Pin Change Interrupt 5)
T1/PCINT4 (Timer/Counter1 Clock Input or Pin Change Interrupt 4)
PDO/MISO/PCINT3 (Programming Data Output or SPI Bus Master Input/Slave Output or
Pin Change Interrupt 3)
PB3
PB2
PDI/MOSI/PCINT2 (Programming Data Input or SPI Bus Master Output/Slave Input or Pin
Change Interrupt 2)
PB1
PB0
SCLK/PCINT1 (SPI Bus Serial Clock or Pin Change Interrupt 1)
SS/PCINT0 (SPI Slave Select input or Pin Change Interrupt 0)
The alternate pin configuration is as follows:
• OC0A/OC1C/PCINT7, Bit 7
OC0A, Output Compare Match A output: The PB7 pin can serve as an external output for the
Timer/Counter0 Output Compare. The pin has to be configured as an output (DDB7 set “one”) to
serve this function. The OC0A pin is also the output pin for the PWM mode timer function.
OC1C, Output Compare Match C output: The PB7 pin can serve as an external output for the
Timer/Counter1 Output Compare C. The pin has to be configured as an output (DDB7 set “one”)
to serve this function. The OC1C pin is also the output pin for the PWM mode timer function.
PCINT7, Pin Change Interrupt source 7: The PB7 pin can serve as an external interrupt source.
• PCINT6, Bit 6
PCINT6, Pin Change Interrupt source 6: The PB6 pin can serve as an external interrupt source.
• PCINT5, Bit 5
PCINT5, Pin Change Interrupt source 5: The PB5 pin can serve as an external interrupt source.
• T1/PCINT4, Bit 4
T1, Timer/Counter1 counter source.
PCINT4, Pin Change Interrupt source 4: The PB4 pin can serve as an external interrupt source.
• PDO/MISO/PCINT3 – Port B, Bit 3
74
AT90USB82/162
7707D–AVR–07/08
ATMEL [ ATMEL ]
