|
Software
Installation
55
Step
4:
Disabled
TXC
signal,
and
the
bit
0
of
the
address
of
4
sets
“0”
5
6
2
Send
out
one
block
data
(Transmit
–
the
data
more
than
two
characters)
Step
1:
Enabled
TXC
signal,
and
the
bit
0
of
the
address
of
4
just
sets
“1”.
Step
2:
Send
out
the
data.
(Write
all
data
to
the
0
of
the
current
COM
port
address)
Step
3:
Wait
for
the
buffer’s
data
empty.
Check
transmitter
holding
register
(THRE,
bit
5
of
the
address
of
5),
and
transmitter
shift
register
(TSRE,
bit
6
of
the
address
of
5)
are
all
sets
must
be
“0”.
Step
4:
Disabled
TXC
signal,
and
the
bit
0
of
the
address
of
4
sets
“0”
5
6
3
Receive
data
The
RS
‐
485’s
operation
of
receiving
data
is
in
the
same
of
the
RS
‐
232’s.
5
6
4
Basic
Language
Example
a.
Initial
86C450
UART
10
OPEN
“COM1:9600,m,8,1”AS
#1
LEN=1
20
REM
Reset
DTR
30
OUT
&H3FC,
(INP(%H3FC)
AND
&HFA)
40
RETURN
b.
Send
out
one
character
to
COM1