Question

为什么用串口的例子程序接受采集的数据出现丢失现象

Answer 1

MSComm.RThreshold = 0 '关闭OnComm事件接收

lblStatus.Caption = "接收"
av = MSComm.Input '读取一个接收字节
dataframe(1) = av(0) '转换为字节

Answer 2

直接上参考程序：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149

Dim av As Variant
Dim datacount As Long

Private Sub cmdClear_Click()
txtData.Text = ""
End Sub

Private Sub cmdStop_Click()

'关闭端口
If MSComm.PortOpen = True Then
MSComm.InBufferCount = 0 '清空缓冲区
MSComm.PortOpen = False
End If

cmdReceive.Enabled = True
lblStatus.Caption = "停止接收，空闲"

End Sub

Private Sub cmdReceive_Click()

'串口设置
With MSComm
.CommPort = 1
.Settings = "9600,N,8,1"
.RThreshold = 1 '接收1字节触发oncomm事件
.InputMode = comInputModeBinary
.InputLen = 1 '输入长度为1
.InBufferCount = 0 '清除接收缓冲区
End With

'打开端口
If MSComm.PortOpen = False Then