Const DQ as Byte = 7
Const CLK as Byte = 8
Const RTS as Byte = 9

Const CONFG_REG as Byte = &H0C
Const CONFG_DS1620 as Byte = &H02
Const READ_STATUS as Byte = &HAC
Const READ_HIGH as Byte = &HA1
Const SET_HIGH as Byte = &H01
Const READ_LOW as Byte = &HA2
Const SET_LOW as Byte = &H02
Const START_CONVERT as Byte = &HEE
Const STOP_CONVERT as Byte = &H22
Const READ_TEMP as Byte = &HAA


Sub Main()
   
   Dim N as Integer
   Dim Dat(1 To 9) as Byte

   Call OpenSerialPort(1, 19200)

   Call RtsLow(RTS)
   Call ClkHigh(CLK)
   Call RtsHigh(RTS)
   Call OutByte_3W(DQ, CONFG_REG)
   Call OutByte_3W(DQ, CONFG_DS1620)
   Call RtsLow(RTS)  
   Sleep 2000


   Call ClkHigh(CLK)
   Call RtsHigh(RTS)
   Call OutByte_3W(DQ, START_CONVERT)
   Call RtsLow(RTS)
   Sleep 200

   Call ClkHigh(CLK)
   Call RtsHigh(RTS)
   Call OutByte_3W(DQ, READ_TEMP)    
  
   For N = 1 to 9
      Call ClkLow(CLK)
      Dat(N) = InByte_3W(DQ)	' fetch the nine bytes        
      Call ClkHigh(CLK) 
   Next
   Call RtsLow(RTS)

   For N = 1 to 9
       Call PutHexB(Dat(N))
       Call PutByte(Asc(" "))
   Next     

   Call NewLine()

   Call ClkHigh(CLK)
   Call RtsHigh(RTS)
   Call OutByte_3W(DQ, STOP_CONVERT)
   Call RtsLow(RTS)

End Sub

Function InByte_3W(ByVal Pin as Byte) as Byte

   Dim N as Integer, IByte as Byte, B as Byte
   For N =1 to 8
      B = Get1Wire(Pin)
      If (B=1) then
         IByte = (IByte\2) OR bx10000000
      Else
         IByte = IByte\2         
      End If
   Next

   InByte_3W = IByte

End Function
           
Sub OutByte_3W(ByVal Pin as Byte, ByVal OByte as Byte)

   Dim N as Integer, B as Byte
   For N = 1 to 8
     B = OByte AND bx00000001
     If (B=1) Then
        Call PutPin(Pin, 1)
     Else
        Call PutPin(Pin, 0)
     End If
     OByte = OByte \ 2
   Next
End Sub      

Sub RtsHigh(ByVal Pin as Byte)
   Call PutPin(Pin, 1)
End Sub

Sub RtsLow(ByVal Pin as Byte)
   Call PutPin(Pin, 0)
End Sub

Sub ClkHigh(ByVal Pin as Byte)
   Call PutPin(Pin, 1)
End Sub

Sub ClkLow(ByVal Pin as Byte)
   Call PutPin(Pin, 0)
End Sub


Sub PutHexB(ByVal X as Byte)	' display a byte in hex format
    Dim Y as Byte
 
    Y= X \ 16 			' convert high nibble to character
    If (Y < 10) then
      Y = Y + Asc("0")
    Else
      Y = Y - 10 + Asc ("A")
    End If
    Call PutByte(Y)

    Y= X And bx00001111 	' same for low nibble
    If (Y < 10) then
      Y = Y + Asc("0")
    Else
      Y = Y - 10 + Asc ("A")
    End If
    Call PutByte(Y)
End Sub