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10.1 Features
10.2 Pin description
Table 87:
UART1 pin description
Pin
Type
RXD1
Input
TXD1
Output
[1]
CTS1
Input
[1]
DCD1
Input
[1]
DSR1
Input
[1]
DTR1
Output
[1]
RI1
Input
[1]
RTS1
Output
[1]
User manual
UM10120
Chapter 10: Universal Asynchronous Receiver/Transmitter 1
(UART1)
Rev. 01 — 24 June 2005
•
UART1 is identical to UART0, with the addition of a modem interface.
•
16 byte Receive and Transmit FIFOs.
•
Register locations conform to '550 industry standard.
•
Receiver FIFO trigger points at 1, 4, 8, and 14 bytes.
•
Built-in baud rate generator.
•
Standard modem interface signals included (LPC2134/6/8 only).
•
LPC2131/2/4/6/8 UART1 provides mechanism that enables implementation of either
software or hardware flow control.
Description
Serial Input. Serial receive data.
Serial Output. Serial transmit data.
Clear To Send. Active low signal indicates if the external modem is ready to accept
transmitted data via TXD1 from the UART1. In normal operation of the modem interface
(U1MCR[4] = 0), the complement value of this signal is stored in U1MSR[4]. State change
information is stored in U1MSR[0] and is a source for a priority level 4 interrupt, if enabled
(U1IER[3] = 1).
Data Carrier Detect. Active low signal indicates if the external modem has established a
communication link with the UART1 and data may be exchanged. In normal operation of
the modem interface (U1MCR[4]=0), the complement value of this signal is stored in
U1MSR[7]. State change information is stored in U1MSR3 and is a source for a priority
level 4 interrupt, if enabled (U1IER[3] = 1).
Data Set Ready. Active low signal indicates if the external modem is ready to establish a
ommunications link with the UART1. In normal operation of the modem interface
(U1MCR[4] = 0), the complement value of this signal is stored in U1MSR[5]. State change
information is stored in U1MSR[1] and is a source for a priority level 4 interrupt, if enabled
(U1IER[3] = 1).
Data Terminal Ready. Active low signal indicates that the UART1 is ready to establish
connection with external modem. The complement value of this signal is stored in
U1MCR[0].
Ring Indicator. Active low signal indicates that a telephone ringing signal has been
detected by the modem. In normal operation of the modem interface (U1MCR[4] = 0), the
complement value of this signal is stored in U1MSR[6]. State change information is stored
in U1MSR[2] and is a source for a priority level 4 interrupt, if enabled (U1IER[3] = 1).
Request To Send. Active low signal indicates that the UART1 would like to transmit data
to the external modem. The complement value of this signal is stored in U1MCR[1].
LPC2134/6/8 only.
Rev. 01 — 24 June 2005
User manual
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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