ATA8741 ATMEL Corporation, ATA8741 Datasheet - Page 84

• Manufacturer Part Number: ATA8741
• Manufacturer: ATMEL Corporation

19.3.2
84
ATA8741
Alternate Functions of Port B
The Port B pins with alternate function are shown in
Table 19-7.
• Port B, Bit 0 – XTAL1/PCINT8
XTAL1: Chip Clock Oscillator pin 1. Used for all chip clock sources except internal calibrateble
RC oscillator. When used as a clock pin, the pin can not be used as an I/O pin. When using
internal calibratable RC Oscillator as a chip clock source, PB0 serves as an ordinary I/O pin.
PCINT8: Pin Change Interrupt source 8. The PB0 pin can serve as an external interrupt source
for pin change interrupt 1.
• Port B, Bit 1 – XTAL2/PCINT9
XTAL2: Chip Clock Oscillator pin 2. Used as clock pin for all chip clock sources except internal
calibrateble RC Oscillator and external clock. When used as a clock pin, the pin can not be used
as an I/O pin. When using internal calibratable RC Oscillator or External clock as a Chip clock
sources, PB1 serves as an ordinary I/O pin.
PCINT9: Pin Change Interrupt source 9. The PB1 pin can serve as an external interrupt source
for pin change interrupt 1.
• Port B, Bit 2 – INT0/OC0A/CKOUT/PCINT10
INT0: External Interrupt Request 0.
OC0A: Output Compare Match output: The PB2 pin can serve as an external output for the
Timer/Counter0 Compare Match A. The PB2 pin has to be configured as an output (DDB2 set
(one)) to serve this function. The OC0A pin is also the output pin for the PWM mode timer
function.
CKOUT - System Clock Output: The system clock can be output on the PB2 pin. The system
clock will be output if the CKOUT Fuse is programmed, regardless of the PORTB2 and DDB2
settings. It will also be output during reset.
PCINT10: Pin Change Interrupt source 10. The PB2 pin can serve as an external interrupt
source for pin change interrupt 1.
Port Pin
PB0
PB1
PB3
PB2
Port B Pins Alternate Functions
Alternate Function
XTAL1: Crystal Oscillator Input.
PCINT8: Pin change interrupt 1 source 8.
XTAL2: Crystal Oscillator Output.
PCINT9: Pin change interrupt 1 source 9.
INT0:
OC0A: Timer/Counter0 Compare Match A output.
CKOUT: System clock output.
PCINT10:Pin change interrupt 1 source 10.
RESET: Reset pin.
dW:
PCINT11:Pin change interrupt 1 source 11.
External Interrupt 0 Input.
debugWire I/O.
Table 19-7 on page
84.
9140B–INDCO–07/09