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Intel
®
IXP42X product line and IXC1100 control plane processors—Universal Asynchronous
Receiver Transceiver (UART)
Intel
®
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
DM September 2006
360 Order Number: 252480-006US
10.5.1.5 Interrupt Enable Register
The DLAB bit in the Line Control Register must be set to logic 0 to access this register.
10.5.1.6 Interrupt Identification Register
In order to minimize software overhead during data character transfers, the UART
prioritizes interrupts into four levels and records these in the Interrupt Identification
register. The Interrupt Identification Register (IIR) stores information indicating that a
prioritized interrupt is pending and the source of that interrupt.
Register Name: IER
Hex Offset Address: 0xC800 1004 Reset Hex Value: 0x00000000
Register
Description:
Interrupt Enable Register
Access: Read/Write.
31 876543210
(Reserved)
DMAE
UUE
NRZE
RTOIE
RIE
RLSE
TIE
RAVIE
Register IER
Bits Name Description
31:8 (Reserved)
7DMAE
DMA Requests Enable:
0 = DMA requests are disabled
1 = DMA requests are enabled
Not Used On the Intel
®
IXP42X product line and IXC1100 control plane
processors.
6 UUE
UART Unit Enable:
0 = the unit is disabled
1 = the unit is enabled
5NRZE
NRZ coding Enable:
0 = NRZ coding disabled
1 = NRZ coding enabled
Not Used On the Intel
®
IXP42X product line and IXC1100 control plane
processors.
4RTOIE
Receiver Time Out Interrupt Enable:
0 = Receiver data Time out interrupt disabled
1 = Receiver data Time out interrupt enabled
3RIE
Modem Interrupt Enable:
0 = Modem Status interrupt disabled
1 = Modem Status interrupt enabled
2RLSE
Receiver Line Status Interrupt Enable:
0 = Receiver Line Status interrupt disabled
1 = Receiver Line Status interrupt enabled
The DLAB bit in the Line Control Register must be set to logic 0 to access this
register.
1TIE
Transmit Data request Interrupt Enable:
0 = Transmit FIFO Data Request interrupt disabled
1 = Transmit FIFO Data Request interrupt enabled
0RAVIE
Receive Data Available Interrupt Enable:
0 = RAVIE interrupt disabled
1 = RAVIE interrupt enabled