UM10429
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User manual
Rev. 1 — 20 October 2010
73 of 258
NXP Semiconductors
UM10429
Chapter 10: LPC1102 Universal Asynchronous Transmitter (UART)
10.5.5 UART Interrupt Identification Register (U0IIR - 0x4004 8008, Read
Only)
U0IIR provides a status code that denotes the priority and source of a pending interrupt.
The interrupts are frozen during a U0IIR access. If an interrupt occurs during a U0IIR
access, the interrupt is recorded for the next U0IIR access.
Bits U0IIR[9:8] are set by the auto-baud function and signal a time-out or end of auto-baud
condition. The auto-baud interrupt conditions are cleared by setting the corresponding
Clear bits in the Auto-baud Control Register.
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 76.
UART Interrupt Enable Register (U0IER - address 0x4000 8004 when DLAB = 0) bit
description
…continued
Bit
Symbol
Value
Description
Reset
value
Table 77.
UART Interrupt Identification Register (U0IIR - address 0x4004 8008, Read Only)
bit description
Bit
Symbol
Value Description
Reset
value
0
IntStatus
Interrupt status. Note that U0IIR[0] is active low. The
pending interrupt can be determined by evaluating
U0IIR[3:1].
1
0
At least one interrupt is pending.
1
No interrupt is pending.
3:1
IntId
Interrupt identification. U0IER[3:1] identifies an interrupt
corresponding to the UART Rx FIFO. All other combinations
of U0IER[3:1] not listed below are reserved (000,
100,101,111).
0
0x3
1 - Receive Line Status (RLS).
0x2
2a - Receive Data Available (RDA).
0x6
2b - Character Time-out Indicator (CTI).
0x1
3 - THRE Interrupt.
5:4
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA
7:6
FIFOEnable
These bits are equivalent to U0FCR[0].
0
8
ABEOInt
End of auto-baud interrupt. True if auto-baud has finished
successfully and interrupt is enabled.
0
9
ABTOInt
Auto-baud time-out interrupt. True if auto-baud has timed
out and interrupt is enabled.
0
31:10 -
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA