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DS18B20温度计

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电梯直达

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发表于 2013-2-28 17:16:54 |只看该作者 |倒序浏览

DS18B20温度计（转载请注明出自http://www.avrbase.com）

　　利用DS18B20做了一个温度计，主要用于测量液体温度。使用效果还不错，现将电路和程序奉上。
　　程序用BASCOM-AVR编写，比较简单，以前从没用过DS18B20，现学现编。采用9位精度，设置好后存入DS18B20的EEPROM。程序没仔细推敲，只是完成简单的显示温度功能。最多显示3位数字，（-10，100）显示1位小数，其它区间显示整数。
　　

'-------------------------------------------------------------------------------
'Name                   : Thermometer(DS18B20).bas
'Copyright             : http://www.avrbase.com
'Micro                   : AtMega8
'Author                : slyt/箫天
'-------------------------------------------------------------------------------
$regfile = "m8def.dat"
$crystal = 8000000
'$baud = 115200

$hwstack = 32
$swstack = 10
$framesize = 40

Config Portb = Output                                     '0-7接LED A-G-DOT
Config Portc = Output                                     '0,1,2分别接LED共阳8,9,12(分别是个位，十位，百位）

'Config Serialin = Buffered , Size = 32
'Config Serialout = Buffered , Size = 32
Config 1wire = Portd.2

Dim Sled As String * 1
Dim Idx As Byte
Dim Temp As Single
Dim Wendu As Single
Dim Waittime As Byte
Dim Ledstring As String * 4
Dim Ledstr As String * 4

Dim Myword As Word
Dim Dsdata(10) As Byte
Dim Myinteger As Integer

Portb = 0
Portc = 0
Osccal = &HB6

'转换精度是9位，精度0.5度,转换时间约为100ms
'先启动一次转换
'(
'初始化指令
1wreset
'发送跳过ID码匹配指令
1wwrite &HCC
'1wreset
'Write Scratchpad(写暂存存储器) [4EH]
1wwrite &H4E
'TH
1wwrite 0
'LH
1wwrite 0
'设置9位转换
1wwrite &H1F

1wreset
1wwrite &HCC                                              '跳过ID码
1wwrite &H48                                              '将RAM的数据写入EEPROM中

Waitus 100
')

1wreset
1wwrite &HCC                                              '跳过ID码
1wwrite &HB8                                              '将EEPROM的数据读到RAM中

1wreset
'发送跳过ID码匹配指令
1wwrite &HCC
'发送温度转换指令
1wwrite &H44

Waitms 100

'(
1wreset
1wwrite &HCC
'读取温度命令
1wwrite &HBE
Dsdata(1) = 1wread(2)

Myinteger = Makeint(dsdata(1) , Dsdata(2))

Temp = Myinteger * 0.0625

If Err = 1 Then
   Ledstring = "----"
   Else
   Ledstring = Fusing(temp , "#.#")
End If

'1wreset
'发送跳过ID码匹配指令
'1wwrite &HCC
'发送温度转换指令
'1wwrite &H44
')

1wreset
1wwrite &HCC
'读取温度命令
1wwrite &HBE
Dsdata(1) = 1wread(2)
Myinteger = Makeint(dsdata(1) , Dsdata(2))
Temp = Myinteger * 0.0625
Ledstring = Fusing(temp , "#.#")

Do

1wreset
1wwrite &HCC
'读取温度命令
1wwrite &HBE
Dsdata(1) = 1wread(2)

Myinteger = Makeint(dsdata(1) , Dsdata(2))
Temp = Myinteger * 0.0625
Wendu = Wendu + Temp

Incr Dsdata(10)

If Dsdata(10) = 10 Then
   Wendu = Wendu / 10

   Ledstr = Fusing(wendu , "#.#")

   If Ledstr <> Ledstring Then
      Ledstring = Ledstr
   End If
   Wendu = 0
   Dsdata(10) = 0
End If

If Len(ledstring) < 4 Then
   Ledstring = "0" + Ledstring
End If

1wreset
'发送跳过ID码匹配指令
1wwrite &HCC
'发送温度转换指令
1wwrite &H44

'显示第一个字符
Waittime = 0
Sled = Mid(ledstring , 1 , 1)
Idx = Val(sled)
If Idx = 0 Then
   If Sled = "-" Then
      Idx = 10
      Portb = Lookup(10 , Leddata)
      Waittime = 8
      Portc = &B100
   End If
   Else
   Portb = Lookup(idx , Leddata)
   Waittime = 8
   Portc = &B100
End If
Waitms Waittime

'显示第二个字符
Sled = Mid(ledstring , 2 , 1)
Idx = Val(sled)
If Sled = "-" Then
   Idx = 10
End If
Portb = Lookup(idx , Leddata)
Portc = &B010
If Mid(ledstring , 3 , 1) = "." Then
   Portb.7 = 0
End If
Waitms 8

'显示第三个字符
Sled = Mid(ledstring , 4 , 1)
Idx = Val(sled)
If Sled = "-" Then
   Idx = 10
End If
Portb = Lookup(idx , Leddata )
Portc = &B001

Loop

End

'LED数字 (0-9)
Leddata:
Data &B11000000 , &B11111001 , &B10100100 , &B10110000 , &B10011001
Data &B10010010 , &B10000010 , &B11111000 , &B10000000 , &B10010000

'"-"
Data &B10111111