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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
300 of 808
NXP Semiconductors
UM10360
Chapter 15: LPC17xx UART1
UART transmitter DMA
In DMA mode, the transmitter DMA request is asserted on the event of the transmitter
FIFO transitioning to not full. The transmitter DMA request is cleared by the DMA
controller.
4.7 UART1 Line Control Register (U1LCR - 0x4001 000C)
The U1LCR determines the format of the data character that is to be transmitted or
received.
4.8 UART1 Modem Control Register (U1MCR - 0x4001 0010)
The U1MCR enables the modem loopback mode and controls the modem output signals.
Table 277: UART1 Line Control Register (U1LCR - address 0x4001 000C) bit description
Bit
Symbol Value Description
Reset
Value
1:0
Word
Length
Select
00
5-bit character length.
0
01
6-bit character length.
10
7-bit character length.
11
8-bit character length.
2
Stop Bit
Select
0
1 stop bit.
0
1
2 stop bits (1.5 if U1LCR[1:0]=00).
3
Parity
Enable
0
Disable parity generation and checking.
0
1
Enable parity generation and checking.
5:4
Parity
Select
00
Odd parity. Number of 1s in the transmitted character and the
attached parity bit will be odd.
0
01
Even Parity. Number of 1s in the transmitted character and the
attached parity bit will be even.
10
Forced "1" stick parity.
11
Forced "0" stick parity.
6
Break
Control
0
Disable break transmission.
0
1
Enable break transmission. Output pin UART1 TXD is forced to
logic 0 when U1LCR[6] is active high.
7
Divisor
Latch
Access
Bit
(DLAB)
0
Disable access to Divisor Latches.
0
1
Enable access to Divisor Latches.
Table 278: UART1 Modem Control Register (U1MCR - address 0x4001 0010) bit description
Bit
Symbol
Value Description
Reset
value
0
DTR
Control
Source for modem output pin, DTR. This bit reads as 0 when
modem loopback mode is active.
0
1
RTS
Control
Source for modem output pin RTS. This bit reads as 0 when
modem loopback mode is active.
0
3-2
-
NA
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
0