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451 interrupt identification register decode, Table 451, “interrupt identification, Uarts—intel – Intel CONTROLLERS 413808 User Manual

Page 673: Non prioritized interrupts, Intel

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Intel

®

413808 and 413812 I/O Controllers in TPER Mode

October 2007

Developer’s Manual

Order Number: 317805-001US

673

UARTs—Intel

®

413808 and 413812

Table 451. Interrupt Identification Register Decode

Interrupt ID bits

Interrupt SET/RESET Function

3 2 1 0 Priority

Type

Source

RESET Control

IP#

0

0

0

1

-

None

No Interrupt is pending.

-

IID[11]

0

1

1

0

Highest

Receiver Line
Status

Overrun Error, Parity Error,
Framing Error, Break
Interrupt.

Reading the Line Status
Register.

IID[10]

0

1

0

0

Second
Highest

Received Data
Available.

Non-FIFO mode: Receive
Buffer is full.

Non-FIFO mode: Reading the
Receiver Buffer Register.

FIFO mode: Trigger level
was reached.

FIFO mode: Reading bytes until
Receiver FIFO drops below
trigger level or setting
RESETRF bit in FCR register.

TOD

1

1

0

0

Second
Highest

Character
Timeout
indication.

FIFO Mode only: At least 1
character is in receiver FIFO
and there was no activity for
a time period.

Reading the Receiver FIFO or
setting RESETRF bit in FCR
register.

IID[01]

0

0

1

0

Third
Highest

Transmit FIFO
Data Request

Non-FIFO mode: Transmit
Holding Register Empty

Reading the IIR Register (when
the source of the interrupt) or
writing into the Transmit
Holding Register.

FIFO mode: Transmit FIFO
has half or less than half
data.

Reading the IIR Register (when
the source of the interrupt) or
writing to the Transmitter FIFO.

IID[00]

0

0

0

0

Fourth
Highest

Modem Status

Clear to Send, Data Set
Ready, Ring Indicator,
Received Line Signal Detect

Reading the Modem Status
Register.

Non Prioritized Interrupts

ABL

4

None

Autobaud Lock
Indication

Autobaud circuitry has
locked onto the baud rate.

Reading the IIR Register