ATMEGA48V_11 ATMEL [ATMEL Corporation], ATMEGA48V_11 Datasheet - Page 78

• Manufacturer Part Number: ATMEGA48V_11
• Description: 8-bit Atmel Microcontroller with 4/8/16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

14.3.1
2545T–AVR–05/11
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. When exter-
nal clock is connected to XTAL1 this pin can 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 clock-
ing 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 con-
nected 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.
Port pin
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
Port B pins alternate functions.
Alternate functions
XTAL2 (chip clock oscillator pin 2)
TOSC2 (timer oscillator pin 2)
PCINT7 (pin change interrupt 7)
XTAL1 (chip clock oscillator pin 1 or external clock input)
TOSC1 (timer oscillator pin 1)
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)
Table
14-3.
ATmega48/88/168
78