Functional Description
Table 19-12. IrDA Mode Interrupts (continued)
UART_IIR Bit
Interrupt Type
Interrupt Source
Interrupt Reset Method
2
Last byte in RX FIFO
Last byte of frame in RX FIFO
Read the UART_RHR register.
is available to be read at the
RHR port.
3
RX overrun
Write to the UART_RHR
Read UART_RESUME register.
register when the RX FIFO is
full.
4
Status FIFO interrupt
Status FIFO triggers level
Read STATUS FIFO.
reached.
5
TX status
1.
UART_THR empty before
1.
Read the UART_RESUME register.
EOF sent. Last bit of
OR
transmission of the IrDA
2.
Read the UART_IIR register.
frame occurred, but with
an underrun error.
OR
2.
Transmission of the last bit
of the IrDA frame
completed successfully.
6
Receiver line status interrupt
CRC, ABORT, or frame-length
Read the STATUS FIFO (read until empty
error is written into the
- maximum of eight reads required).
STATUS FIFO.
7
Received EOF
Received end-of-frame
Read the UART_IIR register.
19.3.5.4 CIR Mode Interrupt Management
19.3.5.4.1 CIR Interrupts
The CIR function generates interrupts that can be enabled and disabled by writing to the appropriate bit in
the interrupt enable register (UARTi.UART_IER). The interrupt status of the device can be checked by
reading the interrupt identification register (UARTi.UART_IIR).
UART, IrDA, and CIR modes have different interrupts in the UART/IrDA/CIR module and, therefore,
different UARTi.UART_IER and UARTi.UART_IIR mappings, depending on the selected mode.
lists the interrupt modes to be maintained. In CIR mode, the sole purpose of the
UARTi.UART_IIR[5] bit is to indicate that the last bit of infrared data was passed to the uart_cts_rctx pin.
Table 19-13. CIR Mode Interrupts
UART_IIR Bit
Interrupt Type
Interrupt Source
Interrupt Reset Method
Number
0
RHR interrupt
DRDY (data ready) (FIFO disable)
Read UART_RHR until interrupt condition
disappears.
RX FIFO above trigger level (FIFO
enable)
1
THR interrupt
TFE (UART_THR empty) (FIFO
Write to the UART_THR register until the
disable)
interrupt condition disappears.
TX FIFO below trigger level (FIFO
enable)
2
RX_STOP_IT
Receive stop interrupt (depending
Read IIR
on value set in the BOF Length
Register (UART_EBLR).
3
RX overrun
Write to RHR when RX FIFO is full.
Read RESUME register.
4
N/A for CIR mode
N/A for CIR mode
N/A for CIR mode
5
TX status
Transmission of the last bit of the
Read the UART_IIR register.
frame is complete successfully.
6
N/A for CIR mode
N/A for CIR mode
N/A for CIR mode
7
N/A for CIR mode
N/A for CIR mode
N/A for CIR mode
3458Universal Asynchronous Receiver/Transmitter (UART)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated