xr16m2650im48 Exar Corporation, xr16m2650im48 Datasheet - Page 27

• Manufacturer Part Number: xr16m2650im48
• Description: High Performance Low Voltage Duart With 32-byte Fifo
• Manufacturer: Exar Corporation

REV. 1.0.2
FCR[5:4]: Transmit FIFO Trigger Select (requires EFR bit-4=1)
(logic 0 = default, TX trigger level = 1)
These 2 bits set the trigger level for the transmit FIFO. The UART will issue a transmit interrupt when the
number of characters in the FIFO falls below the selected trigger level, or when it gets empty in case that the
FIFO did not get filled over the trigger level on last re-load.
must be set to ‘1’ before these bits can be accessed.
FCR[7:6]: Receive FIFO Trigger Select
(logic 0 = default, RX trigger level =1)
These 2 bits are used to set the trigger level for the receive FIFO. The UART will issue a receive interrupt when
the number of the characters in the FIFO crosses the trigger level.
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.
4.6
Line Control Register (LCR) - Read/Write
B
FCR
IT
0
0
1
1
-7
T
ABLE
B
FCR
IT
0
1
0
1
-6
11: T
B
FCR
BIT-1
IT
0
0
1
1
RANSMIT AND
0
0
1
1
-5
HIGH PERFORMANCE LOW VOLTAGE DUART WITH 32-BYTE FIFO
BIT
FCR
0
1
0
1
-4
BIT-0
T
R
0
1
0
1
RIGGER
ECEIVE
8 (default)
R
ECEIVE
16
24
28
27
L
FIFO T
EVEL
Table 11
W
RIGGER
5 (default)
16 (default)
ORD LENGTH
T
T
RANSMIT
L
RIGGER
Table 11
EVEL
6
7
8
24
30
8
L
below shows the selections. EFR bit-4
EVEL
shows the complete selections.
16C550, 16C2550,
16C2552, 16C554,
16C580 compatible.
S
ELECTION
C
OMPATIBILITY
XR16M2650