Philips Semiconductors
SC16C2550
Dual UART with 16 bytes of transmit and receive FIFOs and IrDA
encoder/decoder
Product data
Rev. 03 — 19 June 2003
16 of 46
9397 750 11621
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
7.
Register descriptions
details the assigned bit functions for the SC16C2550 internal registers. The
assigned bit functions are more fully defined in
.
[1]
The value shown in represents the register’s initialized HEX value; X = n/a.
[2]
Accessible only when LCR[7] is logic 0.
[3]
Baud rate registers accessible only when LCR[7] is logic 1.
[4]
Enhanced Feature Register, Xon-1,2 and Xoff-1,2 are accessible only when LCR is set to ‘BF
Hex
’.
Table 7:
SC16C2550 internal registers
Shaded bits are only accessible when EFR[4] is set.
A2
A1
A0
Register Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
General Register Set
0
0
0
RHR
XX
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
0
0
0
THR
XX
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
0
0
1
IER
00
CTS
interrupt
RTS
interrupt
Xoff
interrupt
Sleep
mode
modem
status
interrupt
receive
line
status
interrupt
transmit
holding
register
interrupt
receive
holding
register
0
1
0
FCR
00
RCVR
trigger
(MSB)
RCVR
trigger
(LSB)
reserved
0
reserved
0
DMA
mode
select
XMIT
FIFO
reset
RCVR
FIFO
reset
FIFOs
enable
0
1
0
ISR
01
FIFOs
enabled
FIFOs
enabled
INT
priority
bit 4
INT
priority
bit 3
INT
priority
bit 2
INT
priority
bit 1
INT
priority
bit 0
INT
status
0
1
1
LCR
00
divisor
latch
enable
set break set parity even
parity
parity
enable
stop bits
word
length
bit 1
word
length
bit 0
1
0
0
MCR
00
0
IR
enable
0
loop back OP2/INT
enable
(OP1)
RTS
DTR
1
0
1
LSR
60
FIFO
data
error
THR and
TSR
empty
THR
empty
break
interrupt
framing
error
parity
error
overrun
error
receive
data
ready
1
1
0
MSR
X0
CD
RI
DSR
CTS
∆
CD
∆
RI
∆
DSR
∆
CTS
1
1
1
SPR
FF
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Special Register Set
0
0
0
DLL
XX
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
0
0
1
DLM
XX
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Enhanced Register Set
0
1
0
EFR
00
Auto
CTS
Auto
RTS
Special
char.
select
Enable
IER[4-7],
ISR[4,5],
FCR[4,5],
MCR[5-7]
Cont-3
Tx, Rx
Control
Cont-2
Tx, Rx
Control
Cont-1
Tx, Rx
Control
Cont-0
Tx, Rx
Control
1
0
0
Xon-1
00
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
1
0
1
Xon-2
00
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
1
1
0
Xoff-1
00
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
1
1
1
Xoff-2
00
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8