TQFP/STQFP
PIN #
NAME
89
Data Terminal
Ready 1
SYMBOL
nDTR1
BUFFER
TYPE PER
1
FUNCTION
O6
100
Data Terminal
Ready 2
Ring
Indicator 1
(Note 8)
nDTR2
O6
90
nRI1
I
92
Ring
Indicator 2
(Note 8)
Data Carrier
Detect 1
nRI2
I
91
nDCD1
I
94
Data Carrier
Detect 2
nDCD2
I
DESCRIPTION
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 inactive mode (high). nDTR is
forced inactive during loop mode operation.
Active low Ring Indicator inputs for the serial port.
Handshake signal which notifies the UART that the
telephone ring signal is detected by the modem.
The CPU can monitor the status of nRI signal by
reading bit 6 of Modem Status Register (MSR). A
nRI signal state change from low to high after the
last MSR read will set MSR bit 2 to a 1. If bit 3 of
Interrupt Enable Register is set, the interrupt is
generated when nRI changes state.
Note: Bit 6 of MSR is the complement of nRI.
Active low Data Carrier Detect inputs for the serial
port. Handshake signal which notifies the UART
that carrier signal is detected by the modem. The
CPU can monitor the status of nDCD signal by
reading bit 7 of Modem Status Register (MSR). A
nDCD signal state change from low to high after
the last MSR read will set MSR bit 3 to a 1. If bit 3
of Interrupt Enable Register is set, the interrupt is
generated when nDCD changes state.
Note: Bit 7 of MSR is the complement of nDCD.
95
96
Receive Data 2
Transmit
Data 2
IR Receive
IR Transmit
IR Mode/
IR Receive 3
61
62
63
Receiver serial data input for port 2. IR Receive
Data.
TXD2
O12
Transmit serial data output for port 2. IR transmit
data.
INFRARED INTERFACE
IRRX2
IS
IR Receive.
IRTX2
O12
IR Transmit.
IRMODE/
O6/
IR mode.
IRRX3
IS
IR Receive 3.
PARALLEL PORT INTERFACE (NOTE 3)
RXD2
IS
8
SMSC [ SMSC CORPORATION ]
