
4/29/2020
Loongson 3A3000 / 3B3000 Processor User Manual
93
111
Chinese name:
M Yaodem control register
Register bit width: [7: 0]
Offset:
0x04
Reset value:
0x00
Bit field
Bit field name
Bit width access
description
7: 5
Rese
3
W
Keep
4
L Yaoyao p
1
W
Loopback mode control bit
'0'-normal operation
'1' – Loopback mode. In loopback mode, TXD outputs a
Straight to 1, the output shift register is directly connected to the input shift register
器
中
. The other connections are as follows.
DTR → DSR
RTS → CTS
Out1 → RI
Out2 → DCD
3
OUT2
1
W
Connect to DCD input in loopback mode
2
OUT1
1
W
Connect to RI input in loopback mode
1
RTSC
1
W
RTS signal control bit
0
DTRC
1
W
DTR signal control bit
11.3.7
Line Status Register ( LSR )
Chinese name:
Line status register
Register bit width: [7: 0]
Offset:
0x05
Reset value:
0x00
Bit field
Bit field name
Bit width access
description
Page 116
Godson 3A3000 / 3B3000 Processor User Manual • Volume 1
7
ERROR
1
R
Error indication bit
'1'-at least parity error, framing error or interruption
The broken one.
'0' – no errors
6
TE
1
R
Transmission is empty
'1' – Both the transmission FIFO and the transmission shift register are empty. give
Clear when the transmit FIFO writes data
'0' – with data
5
TFE
1
R
Transmit FIFO bit empty representation bit
'1' – The current transmit FIFO is empty, write data to the transmit FIFO
Time zero
'0' – with data