Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Data Sheet
Product codes
MEGA328P-XMINI
83
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
14.3.1 Alternate Functions of Port B
The Port B pins with alternate functions are shown in
The alternate pin configuration is as follows:
• XTAL2/TOSC2/PCINT7 – Port B, Bit 7
XTAL2: Chip clock Oscillator pin 2. Used as clock pin for crystal Oscillator or Low-frequency crystal Oscillator.
When used as a clock pin, the pin can not be used as an I/O pin.
When used as a clock pin, the pin can not be used as an I/O pin.
TOSC2: Timer Oscillator pin 2. Used only if internal calibrated RC Oscillator is selected as chip clock source,
and the asynchronous timer is enabled by the correct setting in ASSR. When the AS2 bit in ASSR is set (one)
and the EXCLK bit is cleared (zero) to enable asynchronous clocking of Timer/Counter2 using the Crystal
Oscillator, pin PB7 is disconnected from the port, and becomes the inverting output of the Oscillator amplifier. In
this mode, a crystal Oscillator is connected to this pin, and the pin cannot be used as an I/O pin.
and the asynchronous timer is enabled by the correct setting in ASSR. When the AS2 bit in ASSR is set (one)
and the EXCLK bit is cleared (zero) to enable asynchronous clocking of Timer/Counter2 using the Crystal
Oscillator, pin PB7 is disconnected from the port, and becomes the inverting output of the Oscillator amplifier. In
this mode, a crystal Oscillator is connected to this pin, and the pin cannot be used as an I/O pin.
PCINT7: Pin Change Interrupt source 7. The PB7 pin can serve as an external interrupt source.
If PB7 is used as a clock pin, DDB7, PORTB7 and PINB7 will all read 0.
• XTAL1/TOSC1/PCINT6 – Port B, Bit 6
XTAL1: Chip clock Oscillator pin 1. Used for all chip clock sources except internal calibrated RC Oscillator.
When used as a clock pin, the pin can not be used as an I/O pin.
When used as a clock pin, the pin can not be used as an I/O pin.
TOSC1: Timer Oscillator pin 1. Used only if internal calibrated RC Oscillator is selected as chip clock source,
and the asynchronous timer is enabled by the correct setting in ASSR. When the AS2 bit in ASSR is set (one) to
enable asynchronous clocking of Timer/Counter2, pin PB6 is disconnected from the port, and becomes the
and the asynchronous timer is enabled by the correct setting in ASSR. When the AS2 bit in ASSR is set (one) to
enable asynchronous clocking of Timer/Counter2, pin PB6 is disconnected from the port, and becomes the
Table 14-3.
Port B Pins Alternate Functions
Port Pin
Alternate Functions
PB7
XTAL2 (
Chip Clock Oscillator pin 2
)
TOSC2 (
Timer Oscillator pin 2
)
PCINT7 (Pin Change Interrupt 7)
PB6
XTAL1 (
Chip Clock Oscillator pin 1 or External clock input
)
TOSC1 (
Timer Oscillator pin 1
)
PCINT6 (Pin Change Interrupt 6)
PB5
SCK (SPI Bus Master clock Input)
PCINT5 (Pin Change Interrupt 5)
PCINT5 (Pin Change Interrupt 5)
PB4
MISO (SPI Bus Master Input/Slave Output)
PCINT4 (Pin Change Interrupt 4)
PCINT4 (Pin Change Interrupt 4)
PB3
MOSI (SPI Bus Master Output/Slave Input)
OC2A (Timer/Counter2 Output Compare Match A Output)
PCINT3 (Pin Change Interrupt 3)
OC2A (Timer/Counter2 Output Compare Match A Output)
PCINT3 (Pin Change Interrupt 3)
PB2
SS (SPI Bus Master Slave select)
OC1B (Timer/Counter1 Output Compare Match B Output)
PCINT2 (Pin Change Interrupt 2)
OC1B (Timer/Counter1 Output Compare Match B Output)
PCINT2 (Pin Change Interrupt 2)
PB1
OC1A (Timer/Counter1 Output Compare Match A Output)
PCINT1 (Pin Change Interrupt 1)
PCINT1 (Pin Change Interrupt 1)
PB0
ICP1 (Timer/Counter1 Input Capture Input)
CLKO (Divided System Clock Output)
PCINT0 (Pin Change Interrupt 0)
CLKO (Divided System Clock Output)
PCINT0 (Pin Change Interrupt 0)