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UM10850
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© NXP B.V. 2016. All rights reserved.
User manual
Rev. 2.4 — 13 September 2016
265 of 464
NXP Semiconductors
UM10850
Chapter 21: LPC5410x USARTs (USART0/1/2/3)
8
LINMODE
LIN break mode enable.
0
0
Disabled. Break detect and generate is configured for normal operation.
1
Enabled. Break detect and generate is configured for LIN bus operation.
9
CTSEN
CTS Enable. Determines whether CTS is used for flow control. CTS can be from the
input pin, or from the USART’s own RTS if loopback mode is enabled.
0
0
No flow control. The transmitter does not receive any automatic flow control signal.
1
Flow control enabled. The transmitter uses the CTS input (or RTS output in loopback
mode) for flow control purposes.
10
-
Reserved. Read value is undefined, only zero should be written.
NA
11
SYNCEN
Selects synchronous or asynchronous operation.
0
0
Asynchronous mode.
1
Synchronous mode.
12
CLKPOL
Selects the clock polarity and sampling edge of received data in synchronous mode.
0
0
Falling edge. Un_RXD is sampled on the falling edge of SCLK.
1
Rising edge. Un_RXD is sampled on the rising edge of SCLK.
13
-
Reserved. Read value is undefined, only zero should be written.
NA
14
SYNCMST
Synchronous mode Master select.
0
0
Slave. When synchronous mode is enabled, the USART is a slave.
1
Master. When synchronous mode is enabled, the USART is a master.
15
LOOP
Selects data loopback mode.
0
0
Normal operation.
1
Loopback mode. This provides a mechanism to perform diagnostic loopback testing for
USART data. Serial data from the transmitter (Un_TXD) is connected internally to
serial input of the receive (Un_RXD). Un_TXD and Un_RTS activity will also appear on
external pins if these functions are configured to appear on device pins. The receiver
RTS signal is also looped back to CTS and performs flow control if enabled by CTSEN.
17:16 -
Reserved. Read value is undefined, only zero should be written.
NA
18
OETA
Output Enable Turnaround time enable for RS-485 operation.
0
0
Disabled. If selected by OESEL, the Output Enable signal deasserted at the end of the
last stop bit of a transmission.
1
Enabled. If selected by OESEL, the Output Enable signal remains asserted for one
character time after the end of the last stop bit of a transmission. OE will also remain
asserted if another transmit begins before it is deasserted.
19
AUTOADDR
Automatic Address matching enable.
0
0
Disabled. When addressing is enabled by ADDRDET, address matching is done by
software. This provides the possibility of versatile addressing (e.g. respond to more
than one address).
1
Enabled. When addressing is enabled by ADDRDET, address matching is done by
hardware, using the value in the ADDR register as the address to match.
20
OESEL
Output Enable Select.
0
0
Standard. The RTS signal is used as the standard flow control function.
1
RS-485. The RTS signal configured to provide an output enable signal to control an
RS-485 transceiver.
Table 307. USART Configuration register (CFG, offset 0x00) bit description
…continued
Bit
Symbol
Value Description
Reset
Value