DESCRIPTION OF PIN FUNCTIONS
BUFFER
QFP/
TQFP
PIN NO.
TYPE
NAME
SYMBOL
DESCRIPTION
89
Transmit Data 2 TXD2/IRTX
Transmit serial data output for port 2. IR
transmit data.
O24
78
79
Receive Data 1
RXD1
I
Reciever serial data input for port 1.
Transmit serial data output for port 1.
Active low Request to Send outputs for the
Transmit Data 1 TXD1
024
O4
81,91 nRequest to
Send
nRTS1
Serial Port.
notifies modem that the UART is ready to
transmit data. This signal can be
programmed by writing to bit 1 of Modem
Control Register (MCR). The hardware
Handshake output signal
nRTS2
(SYSOPT)
(System Option)
reset will reset the nRTS signal to inactive
mode (high). Forced inactive during loop
mode operation.
At the trailing edge of hardware reset, the
nRTS2 input is latched to determine the
configuration base address.
0 : INDEX Base I/O Address = 3F0 Hex
1 : INDEX Base I/O Address = 370 Hex
83,93 nData Terminal
Ready
nDTR1
nDTR2
Active low Data Terminal Ready outputs for
the serial port. Handshake output signal
notifies modem that the UART is ready to
establish data communication link. This
signal can be programmed by writing to bit
0 of Modem Control Register (MCR). The
hardware reset will reset the nDTR signal to
O4
inactive mode (high).
Forced inactive
during loop mode operation.
9
SMSC [ SMSC CORPORATION ]
