at90ls4433 ATMEL Corporation, at90ls4433 Datasheet - Page 82

• Manufacturer Part Number: at90ls4433
• Description: At90s4433 8-bit Avr Microcontroller With 4k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Port D Schematics
82
AT90S/LS4433
• TXD – Port D, Bit 1
Transmit Data (Data Output pin for the UART). When the UART Transmitter is enabled,
this pin is configured as an output, regardless of the value of DDD1.
• RXD – Port D, Bit 0
Receive Data (Data Input pin for the UART). When the UART Receiver is enabled, this
pin is configured as an input, regardless of the value of DDD0. When the UART forces
this pin to be an input, a logical “1” in PORTD0 will turn on the internal pull-up.
Note that all port pins are synchronized. The synchronization latches are, however, not
shown in the figures.
Figure 57. Port D Schematic Diagram (Pin PD0)
PD0
WP:
WD:
RL:
RP:
RD:
RXD:
RXEN:
MOS
PULL-
UP
WRITE PORTD
WRITE DDRD
READ PORTD LATCH
READ PORTD PIN
READ DDRD
UART RECEIVE DATA
UART RECEIVE ENABLE
RL
RP
Q
Q
PORTD0
RESET
RESET
DDD0
WD
RD
WP
C
C
D
D
RXEN
RXD
1042H–AVR–04/03