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串口通讯遇到接收问题（接收十六进制编码).

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串口通讯遇到接收问题（接收十六进制编码).

发表于：2007-04-22 23:07:31 楼主

我在使用mscomm通讯控件以十六进制码发送没问题,但在写接收时,有问题:对于数字正常,但对于接收 "a-f "的十六制数时,不正常.
private sub form_load（)
dim instring as string
' 使用 com1。
mscomm1.commport = 2
' 9600 波特，无奇偶校验，8 位数据，一个停止位。
mscomm1.settings = "9600,n,8,1 "
' 当输入占用时，
' 告诉控件读入整个缓冲区。
mscomm1.inputlen = 0
' 打开端口。
mscomm1.portopen = true

end sub

'以下过程为发送十六进制编码过程
'请高手写出以下的过程的反过程,也就是接收十六进制编码
private sub cmdoutput_click（)
dim outbuffer（) as byte
dim tem as variant
dim e as integer
dim q as integer
dim lenoftext as integer
lenoftext = len（txtsum.text) \ 2 - 1
redim outbuffer（lenoftext)

if mscomm1.portopen = false then
mscomm1.portopen = true
end if

q = 0
for e = 1 to len（txtsum.text) step 2
tem = mid（txtsum.text, e, 2)
outbuffer（q) = val（ "&h " & tem)
debug.print val（ "&h " & tem)
q = q + 1
next

mscomm1.output = outbuffer
mscomm1.portopen = false

'mscomm1.output
end sub

'以下过程想写接收十六进制编码过程,但对于 'a-f '的编码不正常.请高手指点.
private sub cmdrechex_click（)
'on error goto hander
dim e as integer
dim receivelen as byte
dim inbuffer（) as byte

receivelen = mscomm1.inbuffercount
redim inbuffer（receivelen - 1) as byte

if mscomm1.portopen = false then
mscomm1.portopen = true
end if
inbuffer = mscomm1.input
dim i as byte
dim strcontent as string

for i = 0 to 2 * （receivelen - 1) + 1
debug.print inbuffer（i)
strcontent = strcontent + hex（inbuffer（i))
next i

txtinput.text = strcontent

mscomm1.inbuffercount = 0

'handler:
'if err.number = 9 then resume next

end sub

发表于：2007-04-23 09:32:231楼得分:0

用16进制表示数据，其16进制数的字符范围为00-ff，每两字符0-f表示一接收字节：
private sub mscomm1_oncomm（)
on error resume next
dim bytesreceived（) as byte
dim buffer as string
dim hdata as string
dim i as integer
select case mscomm1.commevent
case comevreceive '接收十六进制数据。并以十六进制显示
mscomm1.inputlen = 0
mscomm1.inputmode = cominputmodebinary '设置当前以二进制数接收数据
buffer = mscomm1.input '接收数据至字符串中
bytesreceived（) = buffer '将数据转入byte中
for i = 0 to ubound（bytesreceived) '显示结果以十六进制显示
if len（hex（bytesreceived（i))) = 1 then
hdata = hdata & "0 " & hex（bytesreceived（i))
else
hdata = hdata & hex（bytesreceived（i))
end if
txtreceive.text = hdata '最后将结果后入txtreceive中
mscomm1.outbuffercount = 0 '清除发送缓冲区
mscomm1.inbuffercount = 0 '清除接收缓冲区
next
end select
end sub

发表于：2007-04-23 11:03:172楼得分:0

private sub cmdrechex_click（)
on error goto handler
dim bytesreceived（) as byte
dim receivelen as byte
dim inbuffer（) as byte
dim hdata as string
dim i as integer
select case mscomm1.commevent
case comevreceive
mscomm1.inputlen = 0
receivelen = mscomm1.inbuffercount
redim inbuffer（receivelen - 1) as byte
inbuffer = mscomm1.input
bytesreceived（) = inbuffer '将数据转入byte中
for i = 0 to ubound（bytesreceived) '显示结果以十六进制显示
if len（hex（bytesreceived（i))) = 1 then
hdata = hdata & "0 " & hex（bytesreceived（i))
else
hdata = hdata & hex（bytesreceived（i))
end if
txtreceive.text = hdata
mscomm1.inbuffercount = 0 '清除接收缓冲区
next
end select
handler:
if err.number = 9 then resume next
end sub

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