DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
282 of 571
NXP Semiconductors
UM10316
Chapter 19: LPC29xx Universal Asynchronous Receiver/Transmitter
While starting transmission of the initial character the CTS1 signal is asserted.
Transmission will stall as soon as the pending transmission has completed. The UART will
continue transmitting a 1 bit as long as CTS1 is deasserted (high). As soon as CTS1 gets
deasserted transmission resumes and a start bit is sent followed by the data bits of the
next character.
4.9 UARTn Line Status Register
The UnLSR is a read-only register that provides status information on the UARTn TX and
RX blocks.
Fig 66. Auto-CTS Functional Timing
start
bits0..7
start
bits0..7
stop
start
bits0..7
stop
UART1 TX
CTS1 pin
~ ~
~ ~
~ ~
~ ~
stop
Table 240. UARTn Line Status Register (U0LSR - address 0xE004 5014,
U1LSR - 0xE004 6014, Read Only) bit description
Bit Symbol
Value Description
Reset
Value
0
Receiver
Data Ready
(RDR)
0
UnLSR0 is set when the UnRBR holds an unread character
and is cleared when the UARTn RBR FIFO is empty.
0
UnRBR is empty.
1
UnRBR contains valid data.
1
Overrun Error
(OE)
0
The overrun error condition is set as soon as it occurs. An
UnLSR read clears UnLSR1. UnLSR1 is set when UARTn
RSR has a new character assembled and the UARTn RBR
FIFO is full. In this case, the UARTn RBR FIFO will not be
overwritten and the character in the UARTn RSR will be lost.
0
Overrun error status is inactive.
1
Overrun error status is active.
2
Parity Error
(PE)
0
When the parity bit of a received character is in the wrong
state, a parity error occurs. An UnLSR read clears UnLSR[2].
Time of parity error detection is dependent on UnFCR[0].
Note:
A parity error is associated with the character at the top
of the UARTn RBR FIFO.
0
Parity error status is inactive.
1
Parity error status is active.