17-16 Intel® PXA26x Processor Family Developer’s Manual

Hardware UART
Table17-9 shows the priority, type, and source of the Interrupt Identification Registe r Inter rupts. It also gives the reset condition used to deassert the Interrupts. Bits (0-3) of the IIR represent priority encoded interrupts. Bits (4-7) do not.
3RTOD
TIME OUT DETECTED (See Section 17.4.2.1.2, “Character Timeout
Interrupt”):
0 – No time out Interrupt is pending
1 – Time out Interrupt is pending. (FIFO mode only)
2:1 R IID[1:0]
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. See
Tabl e 17-1 7)
0RnIP
INTERRUPT PENDING:
0 – Interrupt is pending. (Active low)
1 – No Interrupt is pending
Table 17-8. IIR Bit Definitions (Sheet 2 of 2)
Physical Address
0x4160_0008 Interrupt Identification Reg. (IIR) PXA26x Processor Family Hardware
UART
User
Settings
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
FIFOES
Reserved
ABL
TOD
IID
nIP
Reset ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0 0 ? 0 0 0 0 1
Bits Access Name Description
Table 17-9. Interrupt Identification Register Decode (Sheet 1 of 2)
Interrupt ID bits Interrupt SET/RESET Function
3 2 1 0 Priority Type Source RESET Control
nIP 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 threshold was
reached.
FIFO mode – Reading bytes until
receiver FIFO drops below trigger
threshold or setting RESETRF bit in the
FCR.
TOD 1 1 0 0 Second
Highest
Character
Timeout
indication.
FIFO mode only – At least 1 character
is left in the receive buffer indicating
trailing bytes.
Reading the receiver FIFO or setting
RESETRF bit in the FCR.