UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 458 o f 792
NXP Semiconductors UM10237
Chapter 17: LPC24XX Universal Asynchronous Receiver/Transmitter
4.12 UART1 Scratch Pad Register (U1SCR - 0xE001 001C)

The U1SCR has no effect on the UART1 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 U1SCR has occurred.

4.13 UART1 Auto-baud Control Register (U1ACR - 0xE001 0020)

The UART1 Auto-baud Control Register (U1ACR) 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.

5 DSR Data Set Ready State. Complement of input signal DSR. This bit is
connected to U1MCR[0] in modem loopback mode. 0
6 RI Ring Indicator State. Complement of input RI. This bit is connected
to U1MCR[2] in modem loopback mode. 0
7 DCD Data Carrier Detect State. Complement of input DCD. This bit is
connected to U1MCR[3] in modem loopback mode. 0
Table 409: UART1 Modem Status Register (U1MSR - address 0xE001 0018) bit description
Bit Symbol Value Description Reset
Value
Table 410: UART1 Scratch Pad Register (U1SCR - address 0xE001 0014) bit description
Bit Symbol Description Reset Value
7:0 Pad A readable, writable byte. 0x00
Table 411: Auto-baud Control Register (U1ACR - address 0xE001 0020) bit description
Bit Symbol Value Description Reset value
0 Start This bit is automatically cleared after auto-baud
completion. 0
0 Auto-baud stop (auto-baud is not running).
1 Auto-baud start (auto-baud is running).Auto-baud run
bit. This bit is automatically cleared after auto-baud
completion.
1 Mode Auto-baud mode select bit. 0
0 Mode 0.
1 Mode 1.
2 AutoRestart 0 No restart 0
1 Restart in case of time-out (counter restarts at next
UART1 Rx falling edge) 0
7:3 - N A Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
0
8 ABEOIntClr End of auto-baud interrupt clear bit (write only
accessible). 0
0 Writing a 0 has no impact.
1 Writing a 1 will clear the corresponding interrupt in the
U1IIR.