ST16C2552
16
2.97V TO 5.5V DUAL UART WITH 16-BYTE FIFO
REV. 4.2.2
.
TABLE 7: INTERNAL REGISTERS DESCRIPTION.
ADDRESS
REG
NAME
READ/
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
LCR[7] = 0
0 0 0
THR
WR
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
0 0 1
IER
RD/WR
0
Modem
Stat.
Int.
Enable
RX Line
Stat.
Int.
Enable
TX
Empty
Int
Enable
RX
Data
Int.
Enable
0 1 0
ISR
RD
FIFOs
Enabled
FIFOs
Enabled
0
INT
Source
Bit-3
INT
Source
Bit-2
INT
Source
Bit-1
INT
Source
Bit-0
0 1 0
FCR
WR
RXFIFO
Trigger
Bit-1
RXFIFO
Trigger
Bit-0
0
DMA
Mode
Enable
TX
FIFO
Reset
RX
FIFO
Reset
FIFOs
Enable
0 1 1
LCR
RD/WR Divisor
Enable
Set TX
Break
Set Par-
ity
Even
Parity
Enable
Stop
Bits
Word
Length
Bit-1
Word
Length
Bit-0
1 0 0
MCR
RD/WR
0
Internal
Loop-
back
Enable
OP2#
Output
Control
Rsvd
(OP1#)
RTS#
Output
Control
DTR#
Output
Control
1 0 1
LSR
RD
RX FIFO
Global
Error
THR &
TSR
Empty
THR
Empty
RX
Break
RX
Fram-
ing
Error
RX
Parity
Error
RX
Over-
run
Error
RX
Data
Ready
1 1 0
MSR
RD
CD#
Input
RI#
Input
DSR#
Input
CTS#
Input
Delta
CD#
Delta
RI#
Delta
DSR#
Delta
CTS#
1 1 1
SPR
RD/WR
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
Baud Rate Generator Divisor
0 0 0
DLL
RD/WR
Bit-7
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 1 0
AFR
RD/WR
0
RXRDY#
Select
Baudout#
Select
Concur-
rent Write
4.0 INTERNAL REGISTER DESCRIPTIONS
4.1
Receive Holding Register (RHR) - Read- Only
4.2
Transmit Holding Register (THR) - Write-Only
A2-A0