AT89C5122 ATMEL [ATMEL Corporation], AT89C5122 Datasheet - Page 55

• Manufacturer Part Number: AT89C5122
• Description: MICROCONTROLLER WITH USB AND SMART CARD READER INTERFACES
• Manufacturer: ATMEL [ATMEL Corporation]

Port 3
4202D–SCR–06/05
Port
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
Alternate Functions
Signal
RxD
TxD
INT0
INT1
T0
T1
WR
RD
Description
Receiver data input (asynchronous) or data input/output
(synchronous) of the serial interface
Transmitter data output (asynchronous) or clock output
(synchronous) of the serial interface
External interrupt 0 input/timer 0 gate control input
External interrupt 1input/timer 1 gate control input
Timer 0 counter input
Timer 1 counter input
External Data Memory write strobe; latches the data byte
from port 0 into the external data memory
External Data Memory read strobe; Enables the external
data memory. Port 3 can drive CMOS inputs without external
pull-ups
Port 3 has the following functions:
Port 3 has the following configurations:
Table 32. Port 3 Description
–
–
–
–
Default function: Port 3 is an 8-bit I/O port.
Alternate functions: see table below
Default configuration: Pseudo bi-directional “Port51” digital input/output with
internal pull-ups.
Alternate configurations: See Table 32.
Configurations
Push-pull
Push-pull
Push-pull
Push-pull
Mode 1
KB_OUT
KB_OUT
KB_OUT
KB_OUT
Mode 2
Input WPU
Input WPU
Input WPU
Input WPU
Mode 3
Mode 4
LED0
LED1
LED2
LED3
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