Microcontrollers User manual

UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 433 of 792
NXP Semiconductors
UM10237
Chapter 16: LPC24XX Universal Asynchronous Receiver/Transmitter
4.9 UARTn Scratch Pad Register (U0SCR - 0xE000 C01C, U2SCR -
0xE007 801C U3SCR - 0xE007 C01C)
The UnSCR has no effect on the UARTn 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 UnSCR has occurred.
4.10 UARTn Auto-baud Control Register (U0ACR - 0xE000 C020, U2ACR -
0xE007 8020, U3ACR - 0xE007 C020)
The UARTn Auto-baud Control Register (UnACR) 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.
Table 388: UARTn Scratch Pad Register (U0SCR - address 0xE000 C01C,
U2SCR - 0xE007 801C, U3SCR - 0xE007 C01C) bit description
Bit Symbol Description Reset
Value
7:0 Pad A readable, writable byte. 0x00
Table 389: UARTn Auto-baud Control Register (U0ACR - 0xE000 C020, U2ACR - 0xE007 8020,
U3ACR - 0xE007 C020) 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
UART0 Rx falling edge)
0
7:3 - NA 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). Writing a 1 will clear the corresponding
interrupt in the UnIIR. Writing a 0 has no impact.
0
9 ABTOIntClr Auto-baud time-out interrupt clear bit (write only
accessible). Writing a 1 will clear the corresponding
interrupt in the UnIIR. Writing a 0 has no impact.
0
31:10 - NA Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
0