Rainbow-electronics AT90S2313 Manual de usuario descargar pdf (Pagina 56)

AT90S2313

0839I–AVR–06/02

Port D Data Register – PORTD

Port D Data Direction Register

– DDRD

Port D Input Pins Address –

PIND

The Port D Input Pins address (PIND) is not a register; this address enables access to

the physical value on each Port D pin. When reading PORTD, the Port D Data Latch is

read, and when reading PIND, the logical values present on the pins are read.

Port D as General Digital I/O PDn, general I/O pin: The DDDn bit in the DDRD Register selects the direction of this

pin. If DDDn is set (one), PDn is configured as an output pin. If DDDn is cleared (zero),

PDn is configured as an input pin. If PORTDn is set (one) when configured as an input

pin, the MOS pull-up resistor is activated. To switch the pull-up resistor off, the PORTDn

has to be cleared (zero) or the pin has to be configured as an output pin. The Port D pins

are tri-stated when a reset condition becomes active, even if the clock is not active.

Note: 1. n: 6…0, pin number.

Alternate Functions of Port D The alternate functions of Port D are:

• ICP – Port D, Bit 6

Timer/Counter1 Input Capture pin. See the Timer/Counter1 description for further

details.

• T1 – Port D, Bit 5

T1, Timer 1 Clock source. See the Timer description for further details.

• T0 – Port D, Bit 4

T0, Timer/Counter0 Clock source. See the Timer description for further details.

Bit 76543210

$12 ($32)

– PORTD6 PORTD5 PORTD4 PORTD3 PORTD2 PORTD1 PORTD0 PORTD

Read/Write R R/W R/W R/W R/W R/W R/W R/W

Initialvalue00000000

Bit 76543210

$11 ($31) – DDD6 DDD5 DDD4 DDD3 DDD2 DDD1 DDD0 DDRD

Read/Write R R/W R/W R/W R/W R/W R/W R/W

Initialvalue00000000

Bit 76543210

$10 ($30) – PIND6 PIND5 PIND4 PIND3 PIND2 PIND1 PIND0 PIND

Read/Write R R R RRRRR

Initial value 0 N/A N/A N/A N/A N/A N/A N/A

Table 20. DDDn Bits on Port D Pins

(1)

DDDn PORTDn I/O Pull-up Comment

0 0 Input No Tri-state (High-Z)

0 1 Input Yes PDn will source current if ext. pulled low

1 0 Output No Push-pull Zero Output

1 1 Output No Push-pull One Output

1 2 ... 51 52 53 54 55 56 57 58 59 60 61 ... 91 92

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Rainbow-electronics AT90S2313 Manual de usuario Pagina 56

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