Uart register set – Rainbow Electronics AT76C551 User Manual
Page 62
62
AT76C551
1612D–08/01
UART Register Set
In Table 10, the register file and its fields are briefly presented. A more detailed description is provided in the following
sections.
Table 10. UART Register File and Register Fields
Addr.
(hex)
Register
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
700000
US_RHR
X
X
X
X
X
X
X
X
700000
US_THR
X
X
X
X
X
X
X
X
700004
US_IER
Transmitter
empty
interrupt
Receive
time-out
interrupt
Parity
error
interrupt
Framing
error
interrupt
Overrun
error
interrupt
Receive
break
interrupt
Transmit
holding
register
Receive
holding
register
700008
US_FCR
RCVR
trigger
(MSB)
RCVR
trigger
(LSB)
0
0
DMA
mode
select
0
RCVR
FIFO
reset
FIFO
enable
70000C
US_PMR
Character
length
(MSB)
Character
length
(MSB)
Number of
stop bits
(MSB)
Number of
stop bits
(LSB)
Parity
mode
(PTM2)
Parity
mode
(PTM1)
Parity
type
(PT)
0
700010
US_MR
Channel
mode
(CHM1)
Channel
mode
(CHM0)
0
0
0
0
0
0
700014
US_CSR
Transmitter
empty
Receive
time-out
Parity
error
Framing
error
Overrun
error
Receive
break
Transmit
holding
register
ready
Receive
holding
register
ready
700018
US_CR
Rx
enable
Reset
status bit
Tx enable
Restart
time-out
Tx
teset
Rx
teset
Stop
break
Start
break
70001C
US_BL
MSB
LSB
700020
US_BM
MSB
LSB
700024
US_RTO
MSB
LSB
700028
US_TTG
MSB
LSB
70002C
US_MCI
DSR
RI
CD
CTS
DSR
change
RI change
CD
change
CTS
change
70002C
US_MCO
0
0
0
0
0
0
RTS
DTR
700030
US_MCC
0
LB RI
value
LB CD
value
MC Loop
back
enable
DSR
change
mask
RI change
mask
CD
change
mask
CTS
change
mask