Rainbow-electronics ATmega103L Manual do Utilizador descarregar pdf (Página 83)

ATmega603/103

Port C Schematics

Figure 61. Port C Schematic Diagram (Pins PC0 - PC7)

Port D

Port D is an 8 bit bi-directional I/O port with internal pull-up resistors.

Three I/O memory address locations are allocated for the Port D, one each for the Data Register - PORTD, $12($32), Data

Direction Register - DDRD, $11($31) and the Port D Input Pins - PIND, $10($30). The Port D Input Pins address is read

only, while the Data Register and the Data Direction Register are read/write.

The Port D output buffers can sink 20 mA. As inputs, Port D pins that are externally pulled low will source current if the pull-

up resistors are activated.

Some Port D pins have alternate functions as shown in the following table:

When the pins are used for the alternate function the DDRD and PORTD register has to be set according to the alternate

function description.

Port D Data Register - PORTD

Table 32. Port D Pins Alternate Functions

Port Pin Alternate Function

PD0 INT0 (External Interrupt0 Input)

PD1 INT1

(External Interrupt1 Input)

PD2 INT2

(External Interrupt2 Input)

PD3 INT3 (External Interrupt3 Input)

PD4 IC1 (Timer/Counter1 Input Capture Trigger)

PD6 T1 (Timer/Counter1 Clock Input)

PD7 T2 (Timer/Counter2 Clock Input)

Bit 76543210

$12 PORTD7 PORTD6 PORTD5 PORTD4 PORTD3 PORTD2 PORTD1 PORTD0 PORTD

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

Initial value00000000

DATA B

RESET

PCn

WP:

RL:

SRE:

WRITE PORTC

READ PORTC LATCH

SRAM ADDRESS

EXTERNAL SRAM ENABLE

0-7

PORTCn

SRE

1 2 ... 78 79 80 81 82 83 84 85 86 87 88 ... 125 126

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