xr
XR16C850
REV. 2.3.1
2.97V TO 5.5V UART WITH 128-BYTE FIFO
17
NOTE: Table-B selected as Trigger Table for
FIGURE 11. RECEIVER OPERATION IN NON-FIFO MODE
FIGURE 12. RECEIVER OPERATION IN FIFO AND AUTO RTS FLOW CONTROL MODE
Receive Data Shift
Register (RSR)
Receive
Data Byte
and Errors
RHR Interrupt (ISR bit-2)
Receive Data
Holding Register
(RHR)
RXFIFO1
16X Clock
Receive Data Characters
Data Bit
Validation
Error
Tags in
LSR bits
4:2
Receive Data Shift
Register (RSR)
RXFIFO1
16X Clock
Error
Ta
gs
(128-set
s)
E
rror
Tags
in
LSR
bi
ts
4:2
128 bytes by 11-bit
wide
FIFO
Receive Data Characters
FIFO
Trigger=16
Example
:
- RX FIFO trigger level selected at 16
bytes
(See Note Below)
Data fills to
24
Data falls to
8
Data Bit
Validation
Receive
Data FIFO
Receive
Data
Receive Data
Byte and Errors
RHR Interrupt (ISR bit-2) programmed for
desired FIFO trigger level.
FIFO is Enabled by FCR bit-0=1
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.
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.