Philips LPC213 Series User Manual page 104

Philips Semiconductors
Volume 1
Table 98: UART1 Line Control Register (U1LCR - address 0xE001 000C) bit description
Bit Symbol
6 Break Control
7 Divisor Latch
Access Bit (DLAB)
10.3.9 UART1 Modem Control Register (U1MCR - 0xE001 0010),
LPC2134/6/8 only
The U1MCR enables the modem loopback mode and controls the modem output signals.
Table 99: UART1 Modem Control Register (U1MCR - address 0xE001 0010), LPC2134/6/8 only bit description
Bit Symbol
0 DTR Control
1 RTS Control
3:2 -
4 Loopback Mode
Select
7:5 -
10.3.10 UART1 Line Status Register (U1LSR - 0xE001 0014, Read Only)
The U1LSR is a read-only register that provides status information on the UART1 TX and
RX blocks.
Table 100: UART1 Line Status Register (U1LSR - address 0xE001 0014, read only) bit description
Bit Symbol Value Description
0 Receiver Data
Ready
(RDR)
0
1
User manual
Value Description
0 Disable break transmission.
1 Enable break transmission. Output pin UART1 TXD is forced to
logic 0 when U1LCR[6] is active high.
0 Disable access to Divisor Latches.
1 Enable access to Divisor Latches.
Value Description
Source for modem output pin, DTR. This bit reads as 0 when
modem loopback mode is active.
Source for modem output pin RTS. This bit reads as 0 when
modem loopback mode is active.
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
The modem loopback mode provides a mechanism to perform
diagnostic loopback testing. Serial data from the transmitter is
connected internally to serial input of the receiver. Input pin,
RXD1, has no effect on loopback and output pin, TXD1 is held
in marking state. The four modem inputs (CTS, DSR, RI and
DCD) are disconnected externally. Externally, the modem
outputs (RTS, DTR) are set inactive. Internally, the four modem
outputs are connected to the four modem inputs. As a result of
these connections, the upper four bits of the U1MSR will be
driven by the lower four bits of the U1MCR rather than the four
modem inputs in normal mode. This permits modem status
interrupts to be generated in loopback mode by writing the
lower four bits of U1MCR.
0 Disable modem loopback mode.
1 Enable modem loopback mode.
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
U1LSR[0] is set when the U1RBR holds an unread character and is cleared when
the UART1 RBR FIFO is empty.
U1RBR is empty.
U1RBR contains valid data.
Rev. 01 — 24 June 2005
UM10120
Chapter 10: UART1
Reset value
0
0
Reset value
0
0
NA
0
NA
Reset
value
0
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
104