Rainbow-electronics ATmega103L Manual de usuario descargar pdf (Pagina 84)

ATmega603/103

Port D Data Direction Register - DDRD

Port D Input Pins Address - PIND

The Port D Input Pins address - PIND - is not a register, and 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 con-

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

as an input pin the MOS pull up resistor is activated. To switch the pull up resistor off the PDn has to be cleared (zero) or

the pin has to be configured as an output pin.The port pins are tri-stated when a reset condition becomes active, even if the

clock is not running.

Note: n: 7,6...0, pin number

Alternate Functions of Port D

INT0

.. INT3 - Port D, Bits 0..3

External Interrupt sources 0 - 3. The PD0 - PD3 pins can serve as external active low interrupt sources to the MCU. The

internal pull up MOS resistors can be activated as described above. See the interrupt description for further details, and

how to enable the sources.

IC1 - Port D, Bit 4

IC1 - Input Capture pin for Timer/Counter1. When a positive or negative (selectable) edge is applied to this pin, the con-

tents of Timer/Counter1 is transferred to the Timer/Counter1 Input Capture Register. The pin has to be configured as an

input to serve this function. See the Timer/Counter1 description on how to operate this function. The internal pull up MOS

resistor can be activated as described above.

T1 - Port D, Bit 6

T1, Timer/Counter1 counter source. See the timer description for further details.

T2 - Port D, Bit 7

T2, Timer/Counter2 counter source. See the timer description for further details.

Bit 76543210

$11 DDD7 DDD6 DDD5 DDD4 DDD3 DDD2 DDD1 DDD0 DDRD

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

Initial value00000000

Bit 76543210

$10 PIND7 PIND6 PIND5 PIND4 PIND3 PIND2 PIND1 PIND0 PIND

Read/WriteRRRRRRRR

Initial value Hi-Z Hi-Z Hi-Z Hi-Z Hi-Z Hi-Z Hi-Z Hi-Z

Table 33. DDDn Bits on Port D Pins

DDDn PORTDn I/O Pull up Comment

0 0 Input No Tri-state (Hi-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 ... 79 80 81 82 83 84 85 86 87 88 89 ... 125 126

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Rainbow-electronics ATmega103L Manual de usuario Pagina 84