UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 449 o f 792
NXP Semiconductors UM10237
Chapter 17: LPC24XX Universal Asynchronous Receiver/Transmitter
4.5 UART1 Interrupt Identification Register (U1IIR - 0xE001 0008, Read Only)

The U1IIR provides a status code that denotes the priority and source of a pending

interrupt. The interrupts are frozen during an U1IIR access. If an interrupt occurs during

an U1IIR access, the interrupt is recorded for the next U1IIR access.

7CTS
Interrupt
Enable
If auto-cts mode is enabled this bit enables/disables the
modem status interrupt generation on a CTS1 signal
transition. If auto-cts mode is disabled a CTS1 transition
will generate an interrupt if Modem Status Interrupt Enable
(U1IER[3]) is set.
In normal operation a CTS1 signal transition will generate
a Modem Status Interrupt unless the interrupt has been
disabled by clearing the U1IER[3] bit in the U1IER register.
In auto-cts mode a transition on the CTS1 bit will trigger an
interrupt only if both the U1IER[3] and U1IER[7] bits are
set.
0
0 Disable the CTS interrupt.
1 Enable the CTS interrupt.
8 ABEOIntEn enables the end of auto-baud interrupt. 0
0 Disable End of Auto-baud Interrupt.
1 Enable End of Auto-baud Interrupt.
9 ABTOIntEn enables the auto-baud time-out interrupt. 0
0 Disable Auto-baud Time-out Interrupt.
1 Enable Auto-baud Time-out Interrupt.
31:10 - Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined. NA
Table 401: UART1 Interrupt Enable Register (U1IER - address 0xE001 0004 when DLAB = 0)
bit description
Bit Symbol Value Description Reset
Value
Table 402: UART1 Interrupt Identification Register (U1IIR - address 0xE001 0008, Read Only)
bit description
Bit Symbol Value Description Reset
Value
0 IntStatus
0
Interrupt status. Note that U1IIR[0] is active low. The
pending interrupt can be determined by evaluating
U1IIR[3:1].
1
At least one interrupt is pending.
1 No interrupt is pending.