Rainbow-electronics AT89C5122 Manual de usuario descargar pdf (Pagina 55)

AT8xC5122/23

4202E–SCR–06/06

Port 3 Port 3 has the following functions:

– Default function: Port 3 is an 8-bit I/O port.

– Alternate functions: see table below

Port 3 has the following configurations:

– Default configuration: Pseudo bi-directional “Port51” digital input/output with

internal pull-ups.

– Alternate configurations: See Table 32.

Table 32. Port 3 Description

Port

Alternate Functions Configurations

Signal Description Mode 1 Mode 2 Mode 3 Mode 4

P3.0 RxD

Receiver data input (asynchronous) or data input/output

(synchronous) of the serial interface

Push-pull KB_OUT Input WPU

P3.1 TxD

Transmitter data output (asynchronous) or clock output

(synchronous) of the serial interface

Push-pull KB_OUT Input WPU

P3.2 INT0 External interrupt 0 input/timer 0 gate control input LED0

P3.3 INT1 External interrupt 1input/timer 1 gate control input Push-pull KB_OUT Input WPU

P3.4 T0 Timer 0 counter input Push-pull KB_OUT Input WPU LED1

P3.5 T1 Timer 1 counter input

P3.6 WR

External Data Memory write strobe; latches the data byte

from port 0 into the external data memory

LED2

P3.7 RD

External Data Memory read strobe; Enables the external

data memory. Port 3 can drive CMOS inputs without external

pull-ups

LED3

1 2 ... 50 51 52 53 54 55 56 57 58 59 60 ... 212 213

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Rainbow-electronics AT89C5122 Manual de usuario Pagina 55