XR16L2550IM-F Datasheet, PDF (21/44 Pages) Exar Corporation – LOW VOLTAGE DUART WITH 16-BYTE FIFO

REV. 1.1.3
XR16L2550
LOW VOLTAGE DUART WITH 16-BYTE FIFO
TABLE 8: INTERNAL REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED WHEN EFR BIT-4=1
ADDRESS REG READ/
A2-A0 NAME WRITE
BIT-7
BIT-6
BIT-5
BIT-4 BIT-3 BIT-2 BIT-1 BIT-0
COMMENT
16C550 Compatible Registers
0 0 0 RHR RD Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
0 0 0 THR WR Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
001
IER RD/WR 0/
0/
0/
0/ Modem RX Line TX
RX _{LCR[7] = 0}
Stat. Stat. Empty Data
CTS Int. RTS Int. Xoff Int. Sleep _Int.
Int.
Int
Int.
Enable Enable Enable Mode _{Enable Enable Enable Enable}
Enable
0 1 0 ISR RD FIFOs FIFOs
0/
0/
INT INT INT INT
Enabled Enabled
Source Source Source Source
INT
INT _{Bit-3 Bit-2 Bit-1 Bit-0}
Source Source
Bit-5 Bit-4
LCR ≠ 0xBF
0 1 0 FCR WR RXFIFO RXFIFO 0
Trigger Trigger
0
DMA TX
RX FIFOs
Mode FIFO FIFO Enable
Enable Reset Reset
011
LCR RD/WR Divisor Set TX Set Par- Even Parity Stop Word Word
Enable Break
ity
Parity Enable Bits Length Length
Bit-1 Bit-0
100
MCR RD/WR
0/
BRG
Pres-
caler
0/
IR Mode
ENable
0/
XonAny
Internal
Lopback
Enable
OP2#/
INT
Output
Enable
Rsvd RTS# DTR#
(OP1#) ^{Output Output}
Control Control
1 0 1 LSR RD RX FIFO THR & THR
RX
RX
RX
RX
RX
Global TSR Empty Break Fram- Parity Over- Data LCR ≠ 0xBF
Error Empty
ing Error run Ready
Error
Error
1 1 0 MSR RD
CD#
Input
RI#
Input
DSR#
Input
CTS# Delta Delta Delta Delta
Input CD# RI# DSR# CTS#
1 1 1 SPR RD/WR Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
000
DLL RD/WR Bit-7
Baud Rate Generator Divisor
Bit-6 Bit-5 Bit-4 Bit-3
Bit-2
Bit-1
Bit-0
LCR[7]=1
0 0 1 DLM RD/WR Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
0 0 0 DREV RD
0 0 1 DVID RD
Bit-7
0
Bit-6
0
Bit-5
0
Bit-4
0
Bit-3
0
Bit-2
0
Bit-1
1
Bit-0
0
LCR[7]=1
DLL=0x00
DLM=0x00
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