XRT16C854 Datasheet, PDF (30/54 Pages) Exar Corporation – 2.97V TO 5.5V QUAD UART WITH 128-BYTE FIFO

XR16C854/854D
2.97V TO 5.5V QUAD UART WITH 128-BYTE FIFO
xr
REV. 3.0.1
TABLE 11: TRANSMIT AND RECEIVE FIFO TRIGGER LEVEL SELECTION
FCTR FCTR FCR FCR FCR
BIT-5 BIT-4 BIT-7 BIT-6 BIT-5
1
0
0
0
1
1
0
0
0
1
1
0
1
1
FCR
RECEIVE
BIT-4 TRIGGER LEVEL
0
1
0
1
8
16
56
60
TRANSMIT
TRIGGER
LEVEL
8
16
32
56
COMPATIBILITY
Table-C. 16C654 compatible.
1
1
X
X
X
X Programmable Programmable Table-D. 16L2750, 16C2850,
via TRG
register.
via TRG
register.
16C2852, 16C850, 16C864
compatible.
FCTR[7] = 0. FCTR[7] = 1.
4.6 Line Control Register (LCR) - Read/Write
The Line Control Register is used to specify the asynchronous data communication format. The word or
character length, the number of stop bits, and the parity are selected by writing the appropriate bits in this
register.
LCR[1:0]: TX and RX Word Length Select
These two bits specify the word length to be transmitted or received.
BIT-1
0
0
1
1
BIT-0
0
1
0
1
WORD LENGTH
5 (default)
6
7
8
LCR[2]: TX and RX Stop-bit Length Select
The length of stop bit is specified by this bit in conjunction with the programmed word length.
BIT-2
WORD
LENGTH
STOP BIT LENGTH
(BIT TIME(S))
0
5,6,7,8
1 (default)
1
5
1-1/2
1
6,7,8
2
30