Datasheet

72
7766F–AVR–11/10
ATmega16/32U4
10.3.1 MCU Control Register – MCUCR
• 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 66 for more details about this feature.
10.3.2 Alternate Functions of Port B
The Port B pins with alternate functions are shown in Table 10-3.
The alternate pin configuration is as follows:
• OC0A/OC1C/PCINT7/RTS
, 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.
RTS
: RTS flow control signal used by enhanced UART.
Bit 7 6 5 4 3 2 1 0
JTD – –PUD– – IVSEL IVCE MCUCR
Read/Write R/W R R R/W R R R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Table 10-3. Port B Pins Alternate Functions
Port Pin Alternate Functions
PB7
OC0A/OC1C/PCINT7/RTS
(Output Compare and PWM Output A for
Timer/Counter0, Output Compare and PWM Output C for Timer/Counter1 or Pin
Change Interrupt 7 or UART flow control RTS
signal)
PB6
OC1B/PCINT6/OC.4B/ADC13 (Output Compare and PWM Output B for
Timer/Counter1 or Pin Change Interrupt 6 or Timer 4 Output Compare B / PWM
output or Analog to Digital Converter channel 13)
PB5
OC1A/PCINT5/OC.4B
/ADC12 (Output Compare and PWM Output A for
Timer/Counter1 or Pin Change Interrupt 5 or Timer 4 Complementary Output
Compare B / PWM output or Analog to Digital Converter channel 12)
PB4 PCINT4/ADC11 (Pin Change Interrupt 4 or Analog to Digital Converter channel 11)
PB3
PDO/MISO/PCINT3 (Programming Data Output or SPI Bus Master Input/Slave
Output or Pin Change Interrupt 3)
PB2
PDI/MOSI/PCINT2 (Programming Data Input or SPI Bus Master Output/Slave Input
or Pin Change Interrupt 2)
PB1 SCK/PCINT1 (SPI Bus Serial Clock or Pin Change Interrupt 1)
PB0 SS
/PCINT0 (SPI Slave Select input or Pin Change Interrupt 0)