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Intel® PXA255 Processor Developer’s Manual 10-11
UARTs
3
TOD
(IID3)
Character Timeout Indication Detected:
0 – No Character Timeout Indication interrupt is pending
1 – Character Timeout Indication interrupt is pending (FIFO mode only)
2:1 IID[2:1]
Interrupt Source Encoded:
00 – Modem Status (CTS, DSR, RI, DCD modem signals changed state)
01 – Transmit FIFO request data
10 – Received Data Available
11 – Receive error (Overrun, parity, framing, break, FIFO error)
0IP
Interrupt Pending:
0 – Interrupt is pending (Active low)
1 – No interrupt is pending
Table 10-10. Interrupt Identification Register Decode (Sheet 1 of 2)
Interrupt ID Bits Interrupt SET/RESET Function
3 2 1 0 Priority Type Source Cleared By...
0 0 0 1 — None No interrupt is pending —
0110Highest
Receiver Line
Status
Overrun error, parity error,
framing error, break
interrupt
Reading the LSR
0100
Second
Highest
Received Data
Available
Non-FIFO mode: Receive
buffer is full
FIFO mode: Trigger level
was reached
Non-FIFO mode: Reading
the Receiver Buffer
Register
FIFO mode: Reading bytes
until Receiver FIFO drops
below trigger level or setting
FCR[RESETRF].
Table 10-9. IIR Bit Definitions (Sheet 2 of 2)
Base+0x8 Interrupt Identification Register UART
Bit
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
reserved
FIFOES1
FIFOES0
reserved
reserved
IID3
IID2
IID1
IP
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
Bits Name Description