ST16C2550CQ48 EXAR [Exar Corporation], ST16C2550CQ48 Datasheet - Page 17

• Manufacturer Part Number: ST16C2550CQ48
• Description: 2.97V TO 5.5V DUART WITH 16-BYTE FIFO
• Manufacturer: EXAR [Exar Corporation]

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REV. 4.4.0
.
See “Receiver” on page 13.
See “Transmitter” on page 12.
The Interrupt Enable Register (IER) masks the interrupts from receive data ready, transmit empty, line status
and modem status registers. These interrupts are reported in the Interrupt Status Register (ISR).
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 1 0
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
0 0 0
0 0 1
Receive Holding Register (RHR) - Read- Only
Transmit Holding Register (THR) - Write-Only
Interrupt Enable Register (IER) - Read/Write
N
MCR
RHR
MSR
THR
FCR
SPR
DLM
R
LCR
LSR
DLL
IER
ISR
AME
EG
RD/WR
RD/WR Divisor
RD/WR
RD/WR
RD/WR
RD/WR
W
R
WR
WR
RD
RD
RD
RD
EAD
RITE
/
RX FIFO
RX FIFO
Enabled
Trigger
Enable
FIFOs
Global
B
Error
Input
T
Bit-7
Bit-7
CD#
Bit-7
Bit-7
Bit-7
ABLE
IT
0
0
-7
7: INTERNAL REGISTERS DESCRIPTION
RX FIFO
Enabled
Trigger
Set TX
THR &
FIFOs
Empty
Break
B
Input
Bit-6
Bit-6
TSR
Bit-6
Bit-6
Bit-6
RI#
IT
0
0
-6
16C550 Compatible Registers
Baud Rate Generator Divisor
Set Par-
Empty
DSR#
B
Input
Bit-5
Bit-5
THR
Bit-5
Bit-5
Bit-5
ity
IT
0
0
0
0
-5
17
Internal
Enable
Break
Parity
Loop-
CTS#
B
Even
Input
Bit-4
Bit-4
back
Bit-4
Bit-4
Bit-4
RX
IT
0
0
0
-4
2.97V TO 5.5V DUART WITH 16-BYTE FIFO
Modem
Source
Enable
Enable
Enable
Enable
Output
OP2#/
Fram-
Mode
Parity
B
DMA
Error
Delta
Bit-3
Bit-3
Stat.
Bit-3
CD#
Bit-3
Bit-3
Bit-3
INT
INT
Int.
RX
ing
IT
-3
RX Line
(OP1#)
Enable
Source
Reset
Rsrvd
Parity
B
FIFO
Delta
Error
Bit-2
Bit-2
Bit-2
Stop
Bit-2
Bit-2
Bit-2
Stat.
INT
Bits
RI#
Int.
RX
TX
IT
-2
Source
Control
Enable
Length
Output
Empty
Reset
DSR#
RTS#
Over-
Word
B
FIFO
Error
Delta
Bit-1
Bit-1
Bit-1
Bit-1
Bit-1
Bit-1
Bit-1
INT
RX
RX
run
TX
Int
IT
-1
Control
Enable
Source
Enable
Length
Output
Ready
FIFOs
DTR#
CTS#
B
Word
Delta
Bit-0
Bit-0
Data
Bit-0
Bit-0
Data
Bit-0
Bit-0
Bit-0
INT
RX
Int.
RX
IT
-0
ST16C2550
LCR[7] = 0
LCR[7] = 1
C
OMMENT