XR19L220_07 Datasheet, PDF (39/43 Pages) Exar Corporation – SINGLE CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER

REV. 1.0.1
XR19L220
SINGLE CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER
FIGURE 20. RECEIVE READY INTERRUPT TIMING [FIFO MODE]
Start
Bit
RX
S D0:D7 S D0:D7 T
D0:D7 S D0:D7 T S D0:D7 T S D0:D7 T S D0:D7 T
Stop
Bit
INT
T_SSR
IOR#
(Reading data out
of RX FIFO)
T_SSI
RX FIFO fills up to RX
Trigger Level or RX Data
Timeout
RX FIFO drops
below RX
Trigger Level
T_RRI
RXINTDMA#
FIGURE 21. TRANSMIT READY INTERRUPT TIMING [FIFO MODE]
TX FIFO
Empty
TX
INT*
IER[1]
enabled
IOW#
(Loading data
into FIFO)
Start
Bit
Stop
Bit
S D0:D7 T
ISR is read
S D0:D7 T S D0:D7 T T S D0:D7 T S D0:D7 T
T_SI
ISR is read
TX FIFO fills up
to trigger level
T_WRI
TX FIFO drops
below trigger level
*INT is cleared when the ISR is read or when TX FIFO fills up to the trigger level.
Last Data Byte
Transmitted
S D0:D7 T
TX INT
39