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UM10503
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© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
1131 of 1441
NXP Semiconductors
UM10503
Chapter 40: LPC43xx/LPC43Sxx USART0_2_3
40.6.9 USART Scratch Pad Register
The SCR has no effect on the USART operation. This register can be written and/or read
at user’s discretion. There is no provision in the interrupt interface that would indicate to
the host that a read or write of the SCR has occurred.
40.6.10 USART Auto-baud Control Register
The USART Auto-baud Control Register (ACR) controls the process of measuring the
incoming clock/data rate for the baud rate generation and can be read and written at
user’s discretion.
6
TEMT
Transmitter Empty.
TEMT is set when both THR and TSR are empty; TEMT is
cleared when either the TSR or the THR contain valid data.
1
0
Not empty. THR and/or the TSR contains valid data.
1
Empty. THR and the TSR are empty.
7
RXFE
Error in RX FIFO.
LSR[7] is set when a character with a RX error such as framing
error, parity error or break interrupt, is loaded into the RBR.
This bit is cleared when the LSR register is read and there are
no subsequent errors in the USART FIFO.
0
0
No error. RBR contains no USART RX errors or FCR[0]=0.
1
Error. USART RBR contains at least one USART RX error.
8
TXERR
Error in transmitted character.
A NACK response is given by the receiver in Smart card T=0
mode. This bit is cleared when the LSR register is read.
0
0
No error. No error (normal default condition).
1
NACK. A NACK response is received during Smart card T=0
operation.
31:
9
-
-
Reserved
-
Table 934. USART Line Status Register Read Only (LSR, addresses 0x4008 1014 (USART0),
0x400C 1014 (USART2), 0x400C 2014 (USART3)) bit description
…continued
Bit Symbol
Value
Description
Reset
Value
Table 935. USART Scratch Pad Register (SCR, addresses 0x4008 101C (USART0), 0x400C
101C (USART2), 0x400C 201C (USART3)) bit description
Bit
Symbol
Description
Reset Value
7:0
PAD
Scratch pad. A readable, writable byte.
0x00
31:8
-
Reserved
-