
UM10375
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2011. All rights reserved.
User manual
Rev. 3 — 14 June 2011
188 of 368
NXP Semiconductors
UM10375
Chapter 12: LPC13xx UART
12.6.7 UART Line Control Register (U0LCR - 0x4000 800C)
The U0LCR determines the format of the data character that is to be transmitted or
received.
Table 201. UART FIFO Control Register (U0FCR - address 0x4000 8008, Write Only) bit
description
Bit
Symbol
Value Description
Reset
value
0
FIFOEN
FIFO Enable
0
0
UART FIFOs are disabled. Must not be used in the application.
1
Active high enable for both UART Rx and TX FIFOs and
U0FCR[7:1] access. This bit must be set for proper UART
operation. Any transition on this bit will automatically clear the
UART FIFOs.
1
RXFIFOR
RX FIFO Reset
0
0
No impact on either of UART FIFOs.
1
Writing a logic 1 to U0FCR[1] will clear all bytes in UART Rx
FIFO, reset the pointer logic. This bit is self-clearing.
2
TXFIFOR
TX FIFO Reset
0
0
No impact on either of UART FIFOs.
1
Writing a logic 1 to U0FCR[2] will clear all bytes in UART TX
FIFO, reset the pointer logic. This bit is self-clearing.
3
-
Reserved
0
5:4
-
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
-
7:6
RXTLVL
RX Trigger Level. These two bits determine how many receiver
UART FIFO characters must be written before an interrupt is
activated.
0
0x0
Trigger level 0 (1 character or 0x01).
0x1
Trigger level 1 (4 characters or 0x04).
0x2
Trigger level 2 (8 characters or 0x08).
0x3
Trigger level 3 (14 characters or 0x0E).
31:8 -
-
Reserved
-
Table 202. UART Line Control Register (U0LCR - address 0x4000 800C) bit description
Bit
Symbol Value Description
Reset
Value
1:0
WLS
Word Length Select
0
0x0
5-bit character length.
0x1
6-bit character length.
0x2
7-bit character length.
0x3
8-bit character length.
2
SBS
Stop Bit Select
0
0
1 stop bit.
1
2 stop bits (1.5 if U0LCR[1:0]=00).