UART/IrDA Control and Status Registers
12-68
The interrupt identification register (IIR) is a read-only register, which provides
the source of the interrupt in a prioritized manner.
Table 12–57. UART Mode Interrupt Identification Register (UART_IIR)
Bit
Name
Value
Function
R/W
Reset
Value
7–6
FCR_MIRROR
Mirror the contents of FCR(0) on both bits.
R
00
5–1
IT_TYPE
Priority
5 4 3 2 1
Source
1
0 0 0 1 1
Receiver line status
error
2
0 0 1 1 0
RX time-out
2
0 0 0 1 0
RHR interrupt
3
0 0 0 0 1
THR interrupt
4
0 0 0 0 0
Modem interrupt
5
0 1 0 0 0
XOFF/special
character
6
1 0 0 0 0
CTS, RTS, DSR
change state from
active (low) to
inactive (high)
R
00000
0
IT_PENDING
0
An interrupt is pending (nIRQ active).
R
1
1
No interrupt is pending (nIRQ inactive).