Rainbow-electronics AT90LS4433 Manual do Utilizador descarregar pdf (Página 78)

AT90S/LS4433

1042G–AVR–09/02

Port C Data Register – PORTC

Port C Data Direction Register

– DDRC

Port C Input Pins Address –

PINC

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

the physical value on each Port C pin. When reading PORTC, the Port C Data Latch is

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

Port C as General Digital I/O All six pins in Port C have equal functionality when used as digital I/O pins.

PCn, general I/O pin: The DDCn bit in the DDRC Register selects the direction of this

pin. If DDCn is set (one), PCn is configured as an output pin. If DDCn is cleared (zero),

PCn is configured as an input pin. If PORTCn is set (one) when the pin is configured as

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

PORTCn 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: 1. n: 5..0, pin number

Bit 76543210

$15 ($35)

––PORTC5 PORTC4 PORTC3 PORTC2 PORTC1 PORTC0 PORTC

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

InitialValue00000000

Bit 76543210

$14 ($34) ––DDC5 DDC4 DDC3 DDC2 DDC1 DDC0 DDRC

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

InitialValue00000000

Bit 76543210

$13 ($33) ––PINC5 PINC4 PINC3 PINC2 PINC1 PINC0 PINC

Read/Write R R R RRRRR

Initial Value 0 0 N/A N/A N/A N/A N/A N/A

Table 25. DDCn Effects on Port C Pins

(1)

DDCn PORTCn I/O Pull-up Comment

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

0 1 Input Yes PCn 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 ... 73 74 75 76 77 78 79 80 81 82 83 ... 124 125

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