ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 81

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

14.3.1
9223B–AVR–09/11
Alternate Functions of Port B
The Port B pins with alternate functions are shown in
Table 14-3.
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.
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 asyn-
chronous 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 crys-
tal 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.
Port Pin
Atmel ATmega48PA/88PA/168PA [Preliminary]
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
Port B Pins Alternate Functions
Alternate Functions
XTAL2 (
TOSC2 (
PCINT7 (Pin Change Interrupt 7)
XTAL1 (
TOSC1 (
PCINT6 (Pin Change Interrupt 6)
SCK (SPI Bus Master clock Input)
PCINT5 (Pin Change Interrupt 5)
MISO (SPI Bus Master Input/Slave Output)
PCINT4 (Pin Change Interrupt 4)
MOSI (SPI Bus Master Output/Slave Input)
OC2A (Timer/Counter2 Output Compare Match A Output)
PCINT3 (Pin Change Interrupt 3)
SS (SPI Bus Master Slave select)
OC1B (Timer/Counter1 Output Compare Match B Output)
PCINT2 (Pin Change Interrupt 2)
OC1A (Timer/Counter1 Output Compare Match A Output)
PCINT1 (Pin Change Interrupt 1)
ICP1 (Timer/Counter1 Input Capture Input)
CLKO (Divided System Clock Output)
PCINT0 (Pin Change Interrupt 0)
Chip Clock Oscillator pin 2
Chip Clock Oscillator pin 1 or External clock input
Timer Oscillator pin 2
Timer Oscillator pin 1
)
)
)
Table
14-3.
)
81