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
348 Order Number: 252480-006US
2Receiver Time out occurred:
It happens in FIFO mode only, when there is data in the receive FIFO but no activity for a
time period.
3
Transmitter requests data:
In FIFO mode, the transmit FIFO is half or more than half empty.
In non-FIFO mode, THR is read already.
4
(lowest) Modem Status:
One or more of the modem input signals has changed state.
Register Name: IIR
Hex Offset Address: 0xC800 0008 Reset Hex Value: 0x00000001
Register
Description: Interrupt Identification Register
Access: See below.
31 876543210
(Reserved)
FIFOES
(Rsvd)
TOD
IID
IP_N
Register IIR
Bits Name Description
31:8 (Reserved)
7:6
FIFOES
FIFO Mode Enable Status:
00 = Non-FIFO mode is selected
01 = (Reserved)
10 = (Reserved)
11 = FIFO mode is selected (TRFIFOE = 1)
5:4 (Reserved)
3TOD
Time Out Detected:
0 = No time out interrupt is pending
1 = Time out interrupt is pending. (FIFO mode only)
2:1 IID
Interrupt Source Encoded:
00 = Modem Status (CTS, DSR, RI, DCD modem signals changed state)
01 = Transmit FIFO requests data
10 = Received Data Available
11 = Receive error (Overrun, parity, framing, break, FIFO error)
0IP_N
Interrupt Pending:
0 = Interrupt is pending. (Active low)
1 = No interrupt is pending
Priority Level Interrupt origin