UM10462 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2016. All rights reserved.
User manual Rev. 5.5 — 21 December 2016 267 of 523
NXP Semiconductors
UM10462
Chapter 12: LPC11U3x/2x/1x USART
12.5.20 USART RS-485 Address Match register
The RS485ADRMATCH register contains the address match value for RS-485/EIA-485
mode.
12.5.21 USART RS-485 Delay value register
The user may program the 8-bit RS485DLY register with a delay between the last stop bit
leaving the TXFIFO and the de-assertion of RTS
(or DTR). This delay time is in periods of
the baud clock. Any delay time from 0 to 255 bit times may be programmed.
1 RXDIS Receiver enable. 0
0 The receiver is enabled.
1 The receiver is disabled.
2 AADEN AAD enable. 0
0 Auto Address Detect (AAD) is disabled.
1 Auto Address Detect (AAD) is enabled.
3 SEL Select direction control pin 0
0 If direction control is enabled (bit DCTRL = 1), pin
RTS
is used for direction control.
1 If direction control is enabled (bit DCTRL = 1), pin
DTR
is used for direction control.
4 DCTRL Auto direction control enable. 0
0 Disable Auto Direction Control.
1 Enable Auto Direction Control.
5 OINV Polarity control. This bit reverses the polarity of
the direction control signal on the RTS
(or DTR)
pin.
0
0 The direction control pin will be driven to logic 0
when the transmitter has data to be sent. It will be
driven to logic 1 after the last bit of data has been
transmitted.
1 The direction control pin will be driven to logic 1
when the transmitter has data to be sent. It will be
driven to logic 0 after the last bit of data has been
transmitted.
31:6 - - Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit
is not defined.
NA
Table 253. USART RS485 Control register (RS485CTRL - address 0x4000 804C) bit
description
…continued
Bit Symbol Value Description Reset
value
Table 254. USART RS-485 Address Match register (RS485ADRMATCH - address
0x4000 8050) bit description
Bit Symbol Description Reset value
7:0 ADRMATCH Contains the address match value. 0x00
31:8 - Reserved -
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