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Special function io register – sfior, Alternate functions of port a, Atmega162/v – Rainbow Electronics ATmega162V User Manual

Page 69

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69

ATmega162/V

2513E–AVR–09/03

Special Function IO Register –
SFIOR

• Bit 2 – PUD: Pull-up Disable

When this bit is written to one, the pull-ups in the I/O ports are disabled even if the DDxn
and PORTxn Registers are configured to enable the pull-ups ({DDxn, PORTxn} = 0b01).
See “Configuring the Pin” on page 63 for more details about this feature.

Alternate Functions of Port A

Port A has an alternate function as the address low byte and data lines for the External
Memory Interface and as Pin Change Interrupt.

Table 30 and Table 31 relate the alternate functions of Port A to the overriding signals
shown in Figure 32 on page 67.

Bit

7

6

5

4

3

2

1

0

TSM

XMBK

XMM2

XMM1

XMM0

PUD

PSR2

PSR310

SFIOR

Read/Write

R/W

R/W

R/W

R/W

R/W

R/W

R/W

R/W

Initial Value

0

0

0

0

0

0

0

0

Table 29. Port A Pins Alternate Functions

Port Pin

Alternate Function

PA7

AD7 (External memory interface address and data bit 7)
PCINT7 (Pin Change INTerrupt 7)

PA6

AD6 (External memory interface address and data bit 6)
PCINT6 (Pin Change INTerrupt 6)

PA5

AD5 (External memory interface address and data bit 5)
PCINT5 (Pin Change INTerrupt 5)

PA4

AD4 (External memory interface address and data bit 4)
PCINT4 (Pin Change INTerrupt 4)

PA3

AD3 (External memory interface address and data bit 3)
PCINT3 (Pin Change INTerrupt 3)

PA2

AD2 (External memory interface address and data bit 2)
PCINT2 (Pin Change INTerrupt 2)

PA1

AD1 (External memory interface address and data bit 1)
PCINT1 (Pin Change INTerrupt 1)

PA0

AD0 (External memory interface address and data bit 0)
PCINT0 (Pin Change INTerrupt 0)