Datasheet

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2549O–AVR–05/12

ATmega640/1280/1281/2560/2561

13.3.2 Alternate Functions of Port B

The Port B pins with alternate functions are shown in Table 13-6.

The alternate pin configuration is as follows:

• OC0A/OC1C/PCINT7, 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.

Table 13-5. Overriding Signals for Alternate Functions in PA3:PA0

Signal

Name PA3/AD3 PA2/AD2 PA1/AD1 PA0/AD0

PUOE SRE SRE SRE SRE

PUOV

~(WR | ADA) •

PORTA3 • PUD

~(WR | ADA) •

PORTA2 • PUD

~(WR | ADA) •

PORTA1 • PUD

~(WR | ADA) •

PORTA0 • PUD

DDOE SRE SRE SRE SRE

DDOV WR

| ADA WR | ADA WR | ADA WR | ADA

PVOE SRE SRE SRE SRE

PVOV

A3 • ADA | D3

OUTPUT • WR

A2• ADA | D2

OUTPUT • WR

A1 • ADA | D1

OUTPUT • WR

A0 • ADA | D0

OUTPUT • WR

DIEOE0000

DIEOV0000

DI D3 INPUT D2 INPUT D1 INPUT D0 INPUT

AIO––––

Table 13-6. Port B Pins Alternate Functions

Port Pin Alternate Functions

PB7

OC0A/OC1C/PCINT7 (Output Compare and PWM Output A for Timer/Counter0, Output

Compare and PWM Output C for Timer/Counter1 or Pin Change Interrupt 7)

PB6

OC1B/PCINT6 (Output Compare and PWM Output B for Timer/Counter1 or Pin Change

Interrupt 6)

PB5

OC1A/PCINT5 (Output Compare and PWM Output A for Timer/Counter1 or Pin Change

Interrupt 5)

PB4

OC2A/PCINT4 (Output Compare and PWM Output A for Timer/Counter2 or Pin Change

Interrupt 4)

PB3 MISO/PCINT3 (SPI Bus Master Input/Slave Output or Pin Change Interrupt 3)

PB2 MOSI/PCINT2 (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)