XR16C864 Datasheet, PDF (47/51 Pages) Exar Corporation – 2.97V TO 5.5V QUAD UART WITH 128-BYTE FIFO

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REV. 2.0.1
XR16C864
2.97V TO 5.5V QUAD UART WITH 128-BYTE FIFO
FIGURE 23. TRANSMIT READY & INTERRUPT TIMING [FIFO MODE, DMA MODE DISABLED] FOR CHANNELS A-D
TX FIFO
Empty
TX
(Unloading)
INT*
IER[1]
enabled
TXRDY#
Data in
TX 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
T_WT
IOW#
(Loading data
into FIFO)
*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
T_SRT
TX FIFO
Empty
TXDMA#
47