XR16L2751_05 Datasheet, PDF (15/52 Pages) Exar Corporation – 2.25V TO 5.5V DUART WITH 64-BYTE FIFO AND POWERSAVE

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REV. 1.2.2
XR16L2751
2.25V TO 5.5V DUART WITH 64-BYTE FIFO AND POWERSAVE
FIGURE 9. RECEIVER OPERATION IN NON-FIFO MODE
16X or 8X Clock
(EMSR bit-7)
Receive Data Shift Data Bit
Register (RSR)
Validation
Receive Data Characters
Receive
Data Byte
and Errors
Error
Tags in
LSR bits
4:2
Receive Data
Holding Register
(RHR)
RHR Interrupt (ISR bit-2)
RXFIFO1
FIGURE 10. RECEIVER OPERATION IN FIFO AND AUTO RTS FLOW CONTROL MODE
16X Clock
64 bytes by 11-bit
wide FIFO
Receive Data
Byte and Errors
Receive Data Shift Data Bit
Register (RSR)
Validation
Receive Data Characters
Receive
Data FIFO
Receive
Data
Example:
- RX FIFO trigger level selected at 16 bytes
(See Note below)
Data falls to 8 ^{RTS# re-asserts when data falls below the flow}
control trigger level to restart remote transmitter.
Enable by EFR bit-6=1, MCR bit-1.
FIFO Trigger=16 ^{RHR Interrupt (ISR bit-2) programmed for}
desired FIFO trigger level.
FIFO is Enabled by FCR bit-0=1
Data fills to 24 ^{RTS# de-asserts when data fills above the flow}
control trigger level to suspend remote transmitter.
Enable by EFR bit-6=1, MCR bit-1.
RXFIFO1
NOTE: Table-B selected as Trigger Table for Figure 10 (Table 11).
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