XR16L2751CM EXAR [Exar Corporation], XR16L2751CM Datasheet - Page 24

• Manufacturer Part Number: XR16L2751CM
• Description: 2.25V TO 5.5V DUART WITH 64-BYTE FIFO AND POWERSAVE
• Manufacturer: EXAR [Exar Corporation]

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See “RECEIVER” on page 14.
See “Transmitter” on page 13.
The Baud Rate Generator (BRG) is a 16-bit counter that generates the data rate for the transmitter. The rate is
programmed through registers DLL and DLM which are only accessible when LCR bit-7 is set to ‘1’.
“Programmable Baud Rate Generator” on page 11.
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4.0 INTERNAL REGISTER DESCRIPTIONS
4.1
4.2
4.3
A
A2-A0
DDRESS
0 0 0
0 0 0
0 0 1
0 0 0
0 0 1
0 0 0
0 0 1
0 1 0
1 0 0
1 0 1
1 1 0
1 1 1
T
Receive Holding Register (RHR) - Read- Only
Transmit Holding Register (THR) - Write-Only
Baud Rate Generator Divisors (DLL and DLM) - Read/Write
ABLE
XOFF1 RD/WR
XOFF2 RD/WR
DREV
XON1 RD/WR
XON2 RD/WR
FCTR RD/WR
N
DVID
DLM
TRG
EFR
R
DLL
FC
AME
EG
9: INTERNAL REGISTERS DESCRIPTION.
RD/WR
RD/WR
RD/WR
W
R
WR
RD
RD
RD
EAD
RITE
/
Enable
RX/TX
Mode
B
Bit-7
Bit-7
Bit-7
Bit-7
Bit-7
Auto
CTS
Bit-7
Bit-7
Bit-7
Bit-7
IT
0
-7
SCPAD
Enable
Swap
B
Bit-6
Bit-6
Bit-6
Bit-6
Bit-6
Auto
RTS
Bit-6
Bit-6
Bit-6
Bit-6
IT
0
-6
Baud Rate Generator Divisor
2.25V TO 5.5V DUART WITH 64-BYTE FIFO AND POWERSAVE
Enhanced Registers
Special
Select
Table
B
Char
Bit-5
Bit-5
Bit-5
Bit-5
Bit-5
Bit-1
Bit-5
Bit-5
Bit-5
Bit-5
Trig
IT
0
-5
for more details.
24
IER [7:4],
ISR [5:4],
FCR[5:4],
MCR[7:5]
Enable
B
Table
Bit-4
Bit-4
Bit-0
Bit-4
Bit-4
Bit-4
Bit-4
Bit-4
Bit-4
Bit-4
Trig
IT
0
-4
S
HADED BITS ARE ENABLED WHEN
Direction
Control
RS485
B
ware
Bit-3
Bit-3
Bit-3
Bit-3
Auto
Soft-
Flow
Bit-3
Bit-3
Bit-3
Bit-3
Bit-3
Bit-3
Cntl
IT
1
-3
RX IR
B
Input
ware
Bit-2
Bit-2
Bit-2
Bit-2
Soft-
Flow
Bit-2
Bit-2
Bit-2
Bit-2
Bit-2
Bit-2
Cntl
Inv.
IT
0
-2
B
Bit-1
Bit-1
Bit-1
Soft-
ware
Flow
Bit-1
Bit-1
Bit-1
Bit-1
Bit-1
Bit-1
Bit-1
Bit-1
Auto
RTS
Hyst
Cntl
IT
1
-1
EFR B
B
Soft-
ware
Bit-0
Bit-0
Bit-0
Bit-0
Auto
RTS
Hyst
Bit-0
Flow
Bit-0
Bit-0
Bit-0
Bit-0
Bit-0
Bit-0
Cntl
IT
0
-0
IT
XR16L2751
-4=1
LCR
LCR 0xBF
DLM=0x00
LCR=0
DLL=0x00
C
LCR[7]=1
LCR[7]=1
REV. 1.0.0
OMMENT
0xBF
X
See
BF