Homeautomatisierung mit RS485

[Vitis]

Ja, genau, das nennt sich Protokoll, das der Motor nicht auf das Bremslicht
reagiert, aber da braut jeder Autohersteller sein eigenes Süppchen.
Welcher Befehl was bewirkt ist im CAN nicht festgelegt.
Die Adressaten haben Adressen und bekommen Datenpakete geschickt,
das kann dann das Autoradio sein oder das Fernlicht.
Ob der Adressat Steuergerät Licht nun Fernlicht oder Abblendlicht versteht
hängt von der übermittelten Information ab.
Profibus oder Modbus machen nix Anderes, ein Befehl kommt an, wird
ausgewertet, was der Adressat damit macht ist wieder was Anderes, aber
die Befehlssyntax ist "genormt"

[reinhars]

Der Code funktioniert, ist aber nicht komplett kommentiert und auch nicht aufgeräumt, da ich ihn nur schnell aus einem unfertigen projekt rauskopiert habe.
Aber als start sollte das reichen. Der Master ist auch "unbeffered".

Es wäre natürlich nett wenn wir auch wieder was von dem Hausautomationsprojekt hören oder quellcode bekommen.

Viel Spaß

Grüße Stefan

Master:

' *********** Snap ***********************************
Dim Temp1 As Byte                                           ' Temporäre Variable
Dim Temp2 As Byte                                           ' Temporäre Variable
Dim Tmpw1 As Word
Dim Tmpw2 As Word
Dim Crc As Word                                             ' CRC Word
' *********** Snap Ende ******************************

'############################################################################################
'################################### S.N.A.P. ###############################################
'############################################################################################

' -----[ Title ]------------------------------------------------------
'
' File......: SNAP-IO.BAS
' Purpose...: Turns LEDs on and off
' Author....: Christer Johansson
' Version...: 1.01
' Started...: 980503
' Updated...: 980918
' Modified..: 991229 by Claus Kuehnel
' -----[ Program Description ]----------------------------------------
'
' This program shows how to implement the S.N.A.P protocol in
' BASCOM-AVR and is an simple example to turn LEDs ON or OFF.
' This example uses 16-bit CRC-CCITT as error detection method which
' gives secure data transfer.
'
' The packet structure is defined in the received packets first two
' bytes (HDB2 and HDB1). The following packet structure is used.
'
' DD=01     - 1 Byte destination address
' SS=01     - 1 Byte source address
' PP=00     - No protocol specific flags
' AA=01     - Acknowledge is required
' D=0       - No Command Mode
' EEE=100   - 16-bit CRC-CCITT
' NNNN=0010 - 2 Byte data
'
' Overview of header definition bytes (HDB2 and HDB1)
'
'         HDB2             HDB1
' +-----------------+-----------------+
' | D D S S P P A A | D E E E N N N N |
' +-----------------+-----------------+
'
'


' -----[ Initialization ]---------------------------------------------

Function Slave(command As Byte , Transfer As String , Adresse As Byte , Timeout As Byte)as String
   Const Crcpoly = &H1021                                   ' CRC-CCITT

   Const Preamble_x = &B01001101                            ' Preamble byte
   Const Sbyte_x = &B01010100                               ' Synchronisation byte

   Const Hdb2_x = &H52                                      '01010010
   Const Hdb1_x = &H48                                      '10010000
   Const Myaddress = 1                                      ' Node - Adresse
   Const Empfangen = 1
   Const Senden = 0
   Local Preamble As Byte                                   ' Preamble byte
   Local Sbyte As Byte                                      ' Sync byte
   Local Hdb1 As Byte                                       ' Header Definition Byte 1
   Local Hdb2 As Byte                                       ' Header Definition Byte 2
   Local Dab1 As Byte                                       ' Für welche Node-ID ist das Paket
   Local Sab1 As Byte                                       ' Wer sendet das Paket
   Local Db1 As Byte                                        ' Paket Data Byte 1
   Local Db2 As Byte                                        ' Paket Data Byte 2
   Local Db3 As Byte                                        ' Paket Data Byte 3
   Local Db4 As Byte                                        ' Paket Data Byte 4
   Local Db5 As Byte                                        ' Paket Data Byte 5
   Local Db6 As Byte                                        ' Paket Data Byte 6
   Local Db7 As Byte                                        ' Paket Data Byte 7
   Local Db8 As Byte                                        ' Paket Data Byte 8
   Local Crc2 As Byte                                       ' Paket CRC Hi_Byte
   Local Crc1 As Byte                                       ' Paket CRC Lo_Byte
   Local Received As Byte
   Local Dummy As String * 1

   Adresse = 100 + Adresse

   Db1 = Command
   Dummy = Mid(transfer , 1 , 1)
   Db2 = Asc(dummy)
   Dummy = Mid(transfer , 2 , 1)
   Db3 = Asc(dummy)
   Dummy = Mid(transfer , 3 , 1)
   Db4 = Asc(dummy)
   Dummy = Mid(transfer , 4 , 1)
   Db5 = Asc(dummy)
   Dummy = Mid(transfer , 5 , 1)
   Db6 = Asc(dummy)
   Dummy = Mid(transfer , 6 , 1)
   Db7 = Asc(dummy)
   Dummy = Mid(transfer , 7 , 1)
   Db8 = Asc(dummy)

   Select Case Timeout
      Case 1:
         $timeout = 1000000
      Case 2:
         $timeout = 2000000
      Case 3:
         $timeout = 3000000
      Case 4:
         $timeout = 4000000
      Case Else
         $timeout = 5000000
   End Select

   Preamble = Preamble_x
   Sbyte = Sbyte_x
   Sab1 = Myaddress
   Dab1 = Adresse
   Hdb1 = Hdb1_x
   Hdb2 = Hdb2_x

   Crc = 0
   Temp1 = Hdb2
   Gosub Calc_crc
   Temp1 = Hdb1
   Gosub Calc_crc
   Temp1 = Dab1
   Gosub Calc_crc
   Temp1 = Sab1
   Gosub Calc_crc
   Temp1 = Db8
   Gosub Calc_crc
   Temp1 = Db7
   Gosub Calc_crc
   Temp1 = Db6
   Gosub Calc_crc
   Temp1 = Db5
   Gosub Calc_crc
   Temp1 = Db4
   Gosub Calc_crc
   Temp1 = Db3
   Gosub Calc_crc
   Temp1 = Db2
   Gosub Calc_crc
   Temp1 = Db1
   Gosub Calc_crc
   Crc2 = High(crc)                                         ' Move calculated Hi_CRC value to outgoing packet
   Crc1 = Low(crc)                                          ' Move calculated Lo_CRC value to outgoing packet

   Waitms 10

   ' Send packet to master, including the preamble and SYNC byte
   Printbin #2 , Preamble ; Sbyte ; Hdb2 ; Hdb1 ; Dab1 ; Sab1
   Printbin #2 , Db8 ; Db7 ; Db6 ; Db5 ; Db4 ; Db3 ; Db2 ; Db1
   Printbin #2 , Crc2 ; Crc1

Do
   Received = Waitkey(#2)
   If Received = 0 Then Exit Function
   If Received = Sbyte_x Then
      Inputbin #2 , Hdb2 , Hdb1 , Dab1 , Sab1 , Db8 , Db7 , Db6 , Db5 , Db4 , Db3 , Db2 , Db1 , Crc2 , Crc1       ' Get packet in binary mode
      Goto Packet
   Else
      Preamble = Received
   End If
Loop

Packet:
   If Hdb2 <> Hdb2_x Then
      Locate 3 , 1
      Lcd "hdb2 nicht ok"
      Exit Function
   End If
   If Hdb1 <> Hdb1_x Then
      Locate 3 , 1
      Lcd "hdb1 nicht ok"
      Exit Function
   End If
   If Dab1 <> Myaddress Then
      Locate 3 , 1
      Lcd "adresse nicht ok"
      Exit Function
   End If
   Locate 3 , 1
   Lcd "crccheck"
      Crc = 0
   Temp1 = Hdb2
   Gosub Calc_crc
   Temp1 = Hdb1
   Gosub Calc_crc
   Temp1 = Dab1
   Gosub Calc_crc
   Temp1 = Sab1
   Gosub Calc_crc
   Temp1 = Db8
   Gosub Calc_crc
   Temp1 = Db7
   Gosub Calc_crc
   Temp1 = Db6
   Gosub Calc_crc
   Temp1 = Db5
   Gosub Calc_crc
   Temp1 = Db4
   Gosub Calc_crc
   Temp1 = Db3
   Gosub Calc_crc
   Temp1 = Db2
   Gosub Calc_crc
   Temp1 = Db1
   Gosub Calc_crc
   Temp1 = Crc2
   Gosub Calc_crc
   Temp1 = Crc1
   Gosub Calc_crc
   If Crc <> 0 Then
      Locate 3 , 1
      Lcd "crc nok"
      Exit Function
'      Goto Nak                                              ' Check if there was any CRC errors, if so send NAK
   End If

   '+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++



   Ack_:
   ' Send ACK (i.e tell master that packet was OK)
   Hdb2 = Hdb2 Or &B00000010                                ' Set ACKs bit in HDB2 (xxxxxx10)
   Hdb2 = Hdb2 And &B11111110
   Goto Send

   Nak:
   ' Send NAK (i.e tell master that packet was bad)
   Hdb2 = Hdb2 Or &B00000011                                ' Set ACK bits in HDB2 (xxxxxx11)
   Goto Send

   Send:
   Waitms 50
   ' Swap SAB1 <-> DAB1 address bytes
   Temp2 = Sab1
   Sab1 = Dab1
   Dab1 = Temp2

   Check_crc , Senden

   Crc2 = High(crc)                                         ' Move calculated Hi_CRC value to outgoing packet
   Crc1 = Low(crc)                                          ' Move calculated Lo_CRC value to outgoing packet

   ' Send packet to master, including the preamble and SYNC byte
   Preamble = Preamble_x
   Printbin Preamble ; Sbyte ; Hdb2 ; Hdb1 ; Dab1 ; Sab1
   Printbin Db8 ; Db7 ; Db6 ; Db5 ; Db4 ; Db3 ; Db2 ; Db1
   Printbin Crc2 ; Crc1

'   Goto _start                                              ' Done, go back to Start and wait for a new packet

Slave = Chr(db1) + Chr(db2) + Chr(db3) + Chr(db4) + Chr(db5) + Chr(db6) + Chr(db7) + Chr(db8)

End Function

slave:

' -----[ Title ]------------------------------------------------------
'
' File......: SNAP-IO.BAS
' Purpose...: Turns LEDs on and off
' Author....: Christer Johansson
' Version...: 1.01
' Started...: 980503
' Updated...: 980918
' Modified..: 991229 by Claus Kuehnel
' -----[ Program Description ]----------------------------------------
'
' This program shows how to implement the S.N.A.P protocol in
' BASCOM-AVR and is an simple example to turn LEDs ON or OFF.
' This example uses 16-bit CRC-CCITT as error detection method which
' gives secure data transfer.
'
' The packet structure is defined in the received packets first two
' bytes (HDB2 and HDB1). The following packet structure is used.
'
' DD=01     - 1 Byte destination address
' SS=01     - 1 Byte source address
' PP=00     - No protocol specific flags
' AA=01     - Acknowledge is required
' C=0       - No Command Mode
' EEE=100   - 16-bit CRC-CCITT
' NNNN=1000 - 8 Byte data
'
' Overview of header definition bytes (HDB2 and HDB1)
'
'         HDB2             HDB1
' +-----------------+-----------------+
' | D D S S P P A A | C E E E N N N N |
' +-----------------+-----------------+
'
'
' *********** SNAP **********************************
Const Preamble_x = &B01010011                               ' Preamble byte
Const Sbyte = &B01010100                                    ' Synchronisation byte
Const Crcpoly = &H1021                                      ' CRC-CCITT
Const Hdb2_x = &H52                                         '01010010
Const Hdb1_x = &H48                                         '01001000
Const Empfangen = 1
Const Senden = 0

' *********** 1-Wire Sensoren ************************
   Dim Temp_aussen As Integer
' *********** Ende 1-Wire Sensoren *******************

   Dim A As Byte                                            'Zähler für For...Next und die Bus-Arrays
   Dim Bytearray(4) As Byte                                 'Bytearray für allgemeine Nutzung

   Dim Transfer As String * 8

'*********** SNAP ************************************
Dim Adresse As Byte                                         ' Node - Adresse
Dim Preamble As Byte                                        ' Preamble byte
Dim Lastbyte As Byte
Dim Hdb1 As Byte                                            ' Header Definition Byte 1
Dim Hdb2 As Byte                                            ' Header Definition Byte 2
Dim Dab1 As Byte                                            ' Für welche Node-ID ist das Paket
Dim Sab1 As Byte                                            ' Wer sendet das Paket
Dim Db1 As Byte                                             ' Paket Data Byte 1
Dim Db2 As Byte                                             ' Paket Data Byte 2
Dim Db3 As Byte                                             ' Paket Data Byte 3
Dim Db4 As Byte                                             ' Paket Data Byte 4
Dim Db5 As Byte                                             ' Paket Data Byte 5
Dim Db6 As Byte                                             ' Paket Data Byte 6
Dim Db7 As Byte                                             ' Paket Data Byte 7
Dim Db8 As Byte                                             ' Paket Data Byte 8
Dim Crc2 As Byte                                            ' Paket CRC Hi_Byte
Dim Crc1 As Byte                                            ' Paket CRC Lo_Byte
Dim Received As Byte                                        ' Temporäre Variable
Dim Temp1 As Byte
Dim Temp2 As Byte                                           ' Temporäre Variable
Dim Crc As Word                                             ' CRC Word
Dim Tmpw1 As Word
Dim Tmpw2 As Word
Dim I As Integer
Dim Dummy As String * 1

Declare Sub Check_crc(byval Modus As Byte)

'******************* Schnittstellen, LCD, usw ********
Config Com1 = Dummy , Synchrone = 0 , Parity = None , Stopbits = 1 , Databits = 8 , Clockpol = 0       ' MUST MATCH THE SLAVE
Rs485dir Alias Portd.2
Config Print = Portd.2 , Mode = Set                         ' use portb.1 for the direction
Config Rs485dir = Output
Rs485dir = 0                                                ' go to receive mode



   Config Portc.0 = Input
   Config Portc.1 = Input
   Config Portc.2 = Input
   Portc.0 = 1
   Portc.1 = 1
   Portc.2 = 1


If Adresse = 0 Then
Adresse = 100
   If Pinc.0 = 0 Then Adresse = Adresse + 2
   If Pinc.1 = 0 Then Adresse = Adresse + 4
   If Pinc.2 = 0 Then Adresse = Adresse + 8
End If

'------[ Program ]----------------------------------------------------
 Print "node up"

Do
Received = Waitkey()
If Received = Sbyte Then
   Inputbin Hdb2 , Hdb1 , Dab1 , Sab1 , Db8 , Db7 , Db6 , Db5 , Db4 , Db3 , Db2 , Db1 , Crc2 , Crc1       ' Get packet in binary mode
   Gosub Packet
Else
   Preamble = Received
End If
Loop
End

Packet:
   If Hdb2 <> Hdb2_x Then
      Print "hdb2 nicht ok"
      Return
   End If

   If Hdb1 <> Hdb1_x Then
      Print "hdb1 nicht ok"
      Return
   End If

   If Dab1 <> Adresse Then
      Print "adresse nicht ok"
      Return
   End If

   Print "crccheck"
   Check_crc , Empfangen                                    ' Check CRC for all the received bytes
   If Crc <> 0 Then
      Print "crc nok"
      Goto Nak                                              ' Check if there was any CRC errors, if so send NAK
   End If
   ' No CRC errors in packet so check what to do.
   ' Associated Function (place it between +++ lines)
   '+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
      Transfer = Chr(db2) + Chr(db3) + Chr(db4) + Chr(db5) + Chr(db6) + Chr(db7) + Chr(db8)
      Select Case Db1
      Print "prepare data"
      Case 50:
         Goto $0c00

      Case 10:
         #if Devel
            Print "Temperatur!!!"
            'Gosub Temperatur
            Print "TWI:" ; Twi
            Print "Register:" ; Str(register)
            Print "twi_btw:" ; Str(twi_btw)
         #endif
         Gosub Temperatur
'         Transfer = Temperatur$
      Case Else
         Print "command: " ; Db1
      End Select


   Dummy = Mid(transfer , 1 , 1)
   Db1 = Asc(dummy)
   Dummy = Mid(transfer , 2 , 1)
   Db2 = Asc(dummy)
   Dummy = Mid(transfer , 3 , 1)
   Db3 = Asc(dummy)
   Dummy = Mid(transfer , 4 , 1)
   Db4 = Asc(dummy)
   Dummy = Mid(transfer , 5 , 1)
   Db5 = Asc(dummy)
   Dummy = Mid(transfer , 6 , 1)
   Db6 = Asc(dummy)
   Dummy = Mid(transfer , 7 , 1)
   Db7 = Asc(dummy)
   Dummy = Mid(transfer , 8 , 1)
   Db8 = Asc(dummy)


   '+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

   Ack_:
   ' Send ACK (i.e tell master that packet was OK)
   Hdb2 = Hdb2 Or &B00000010                                ' Set ACKs bit in HDB2 (xxxxxx10)
   Hdb2 = Hdb2 And &B11111110
   Goto Send

   Nak:
   ' Send NAK (i.e tell master that packet was bad)
   Hdb2 = Hdb2 Or &B00000011                                ' Set ACK bits in HDB2 (xxxxxx11)
   Goto Send

   Send:
   Waitms 50
   ' Swap SAB1 <-> DAB1 address bytes
   Temp2 = Sab1
   Sab1 = Dab1
   Dab1 = Temp2

   Check_crc , Senden

   Crc2 = High(crc)                                         ' Move calculated Hi_CRC value to outgoing packet
   Crc1 = Low(crc)                                          ' Move calculated Lo_CRC value to outgoing packet

   ' Send packet to master, including the preamble and SYNC byte
   Preamble = Preamble_x
   Printbin Preamble ; Sbyte ; Hdb2 ; Hdb1 ; Dab1 ; Sab1
   Printbin Db8 ; Db7 ; Db6 ; Db5 ; Db4 ; Db3 ; Db2 ; Db1
   Printbin Crc2 ; Crc1

'   Goto _start                                              ' Done, go back to Start and wait for a new packet
Return

' -----[ Subroutines ]------------------------------------------------
'
'Soubroutine for checking all received bytes in packet
Sub Check_crc(modus As Byte)
'Const Empfangen = 1
'Const Senden = 0
   Crc = 0
   Temp1 = Hdb2
   Gosub Calc_crc
   Temp1 = Hdb1
   Gosub Calc_crc
   Temp1 = Dab1
   Gosub Calc_crc
   Temp1 = Sab1
   Gosub Calc_crc
   Temp1 = Db8
   Gosub Calc_crc
   Temp1 = Db7
   Gosub Calc_crc
   Temp1 = Db6
   Gosub Calc_crc
   Temp1 = Db5
   Gosub Calc_crc
   Temp1 = Db4
   Gosub Calc_crc
   Temp1 = Db3
   Gosub Calc_crc
   Temp1 = Db2
   Gosub Calc_crc
   Temp1 = Db1
   Gosub Calc_crc
   If Modus = Empfangen Then
      Temp1 = Crc2
      Gosub Calc_crc
      Temp1 = Crc1
      Gosub Calc_crc
   End If
End Sub

' Subroutine for calculating CRC value in variable Tmp_Byte1
Calc_crc:
   Tmpw1 = Temp1 * 256
   Crc = Tmpw1 Xor Crc
   For Temp2 = 0 To 7
      If Crc.15 = 0 Then Goto Shift_only
      Tmpw2 = Crc * 2
      Crc = Tmpw2 Xor Crcpoly
      Goto Nxt
      Shift_only:
         Crc = Crc * 2
      Nxt:
   Next
Return

[Ramer]

@reinhars
Wo definierst du genau ob es sich um den Master oder Slave handelt?
Beim Slave sehe ich richtig das du die Adressierung per Hardware gelöst hast?

If Adresse = 0 Then
Adresse = 100
If Pinc.0 = 0 Then Adresse = Adresse + 2
If Pinc.1 = 0 Then Adresse = Adresse + 4
If Pinc.2 = 0 Then Adresse = Adresse + 8
End If

So haste entweder Adresse 102,104,106,108,110,112 ist das Richtig so?

Ja werde das Projekt wenn ich was zum vorzeigen habe komplett uploaden, auch einzeln das Protokoll etc. Hardwarepläne,Bilder etc.

[reinhars]

Der kleine unterschied bei diesem Master/Slave-Code ist, dass der Slave die ganze zeit lauscht und auf entsprechende kommandos reagiert. Ich verwende hier db1 (databyte 1) als kommandobyte um dem Slave zu sagen welche aufgabe er erfüllen soll. in den restlichen databytes kann ich noch parameter übergeben.
der slave überträgt dann db1-db8 als ergebniss.
Ich werte nicht alle ack´s und nack´s aus weil ja das projekt noch nicht fertig ist.
Das mit der Adressierung ist so richtig - ich verwende momentan jumper und später bcd-codierschalter.
Die Adressierung kann natürlich auch in software gelöst werden und z.b. über eine gencall-adresse programmiert werden.
Bei meinem projekt ist jedoch die einstellung per hardware sinvoller, weil dann eine optische kontrollmöglichkeit der einstellung möglich ist.

[Vitis]

hab mir mal gestern Abend die Routinen vorgenommen und angefangen für
"universellere" Verwendung umzuschreiben. Die erste Aktion ist der Slave,
den Empfang hab ich schon auf Interruptbasierend umgebaut inklusive
Timeout per Timerinterrupt wenn Zeichen verloren gehen. Die zweite
Baustelle war die Auswertung von hdb1 und hdb2, das errechnen der
Framelänge aus den dort eingehenden Angaben zur Bytezahl Adresse
Sender u. Slave, sowie die Datenbyteanzahl, crc8 crc16 crc32 Ack und
Nack ...
heut abend werd ich wenn mir mein Kleiner n paar Minütchen Zeit lässt
wieder dran gehen.

[Vitis]

Gestern hab ich die verschiedenen Prüfungen CRC8, CRC16,CRC32 etc. nochmal überarbeitet sowie die Ack-verarbeitung, die Flagbytes sind auch
schon drinnen und die Response angefangen ... heut nacht gehts weiter

[Ramer]

Vitis du bist einfach der beste!^^

Bin momentan auch drann am "herum spielen" mit SNAP, habe es allerdings noch nicht gescheit zum laufen gebracht. Aber wird schon kommen.^^

[Vitis]

erst loben wenn "habe fertig" ... sonst lass ich noch den hammer fallen

[Achim S.]

Hallo
kann mich erinnern, das ich bei ELV einen Bus gesehen habe der mit diesem System läuft. Vielleicht kann es weiter bringen.
Achim

[Vitis]

mal ein zwischenstand:

$regfile = "m8def.dat"
$crystal = 8000000
$hwstack = 70                                               ' default use 32 for the hardware stack
$swstack = 250                                              ' default use 10 for the SW stack
$framesize = 80


$baud = 19200

' Konfiguration zum Kompilieren
Const Max_framelen = 32
Dim Slaveaddress As Byte
' dim slaveaddress as word
Slaveaddress = &B00000011

Dim Tx_data(max_framelen) As Byte
Dim Tx_string As String * Max_framelen At Tx_data Overlay
#if Max_framelen > 255
   Dim Tx_pointer As Word
#else
   Dim Tx_pointer As Byte
#endif

Dim Rx_data(max_framelen) As Byte
Dim Rx_string As String * Max_framelen At Rx_data Overlay
#if Max_framelen > 255
   Dim Rx_pointer As Word
#else
   Dim Rx_pointer As Byte
#endif

Dim Data_array(max_framelen) As Byte
Dim Flag_array(3) As Byte

Dim Rx_flag As Byte
Dim Timerflag As Byte
Dim Frame_receive_flag As Byte

Declare Sub Rx_verarbeitung()

' Interrupts initialisieren
On Urxc Zeichenempfang
Enable Urxc


Config Timer0 = Timer , Prescale = 1024
On Timer0 Timer_irq
Const Timervorgabe = 178

Disable Timer0
Enable Interrupts


' Mainloop
Do
'Hier könnte Ihr Hauptprogramm stehen


   If Timerflag = 1 Then
      Timerflag = 0
      ' verarbeitung
          Print Rx_string
          Call Rx_verarbeitung()
      Rx_pointer = 0
      Rx_flag = 0
   End If
   If Rx_flag = 1 And Rx_data(1) = &B01010100 And Rx_pointer > 3 Then
      Call Rx_verarbeitung()
   End If
Loop



Timer_irq:
   Timer0 = 0
   Timerflag = 1
   Disable Timer0
   Incr Rx_pointer
   Rx_data(rx_pointer) = 0
Return

Zeichenempfang:
   Timer0 = Timervorgabe
   Enable Timer0
   Rx_flag = 1
   If Rx_pointer < 19 Then
      Incr Rx_pointer
      Rx_data(rx_pointer) = Udr
   End If
Return


Sub Rx_verarbeitung()
   Local Hdb2_rx As Byte
   Local Hdb1_rx As Byte

   Local Dd_num As Byte
   Local Ss_num As Byte
   Local Pp_num As Byte
   Local Aa_num As Byte
   Local Eee_num As Byte

   Local Checksum_var As Word
   Local Checksum_byte_1 As Byte
   Local Checksum_byte_2 As Byte
   Local Checksum_check_flag As Byte
   Local Checksum_long As Long

   Local Temp_variable_1 As Word
   Local Temp_variable_2 As Word
   Local Temp_variable_3 As Word
   Local Temp_variable_4 As Word
   Local Nnnn_num As Word

   Local Rx_bytes_to_load As Word
   Local Slaveaddress_check_flag As Byte

   ' für test:
   Rx_pointer = 8
   Rx_data(1) = &B01010100
   Rx_data(2) = &B01010001
   Rx_data(3) = &B01000001
   Rx_data(4) = &B00000011
   Rx_data(5) = &B00000001
   Rx_data(6) = &B11110000
   Rx_data(7) = &B00100010
   Rx_data(8) = &B00110101


   ' hdb2
   Dd_num = Rx_data(2)
   Shift Dd_num , Right , 6

   Ss_num = Rx_data(2)
   Ss_num = Ss_num And &B00110000
   Shift Ss_num , Right , 4

   Pp_num = Rx_data(2)
   Pp_num = Pp_num And &B00001100
   Shift Pp_num , Right , 2

   Aa_num = Rx_data(2)
   Aa_num = Aa_num And &B00000011

   ' hdb1
   Eee_num = Rx_data(3)
   Eee_num = Eee_num And &B01110000
   Shift Eee_num , Right , 4

   Nnnn_num = Rx_data(3)
   Nnnn_num = Nnnn_num And &B00001111

   ' add framelength
   Select Case Nnnn_num
      Case &B00000000
           Rx_bytes_to_load = 0
      Case &B00000001
           Rx_bytes_to_load = 1
      Case &B00000010
           Rx_bytes_to_load = 2
      Case &B00000011
           Rx_bytes_to_load = 3
      Case &B00000100
           Rx_bytes_to_load = 4
      Case &B00000101
           Rx_bytes_to_load = 5
      Case &B00000110
           Rx_bytes_to_load = 6
      Case &B00000111
           Rx_bytes_to_load = 7
      Case &B00001000
           Rx_bytes_to_load = 8
      Case &B00001001
           Rx_bytes_to_load = 16
      #if Max_framelen > 16
      Case &B00001010
           Rx_bytes_to_load = 32
      #endif
      #if Max_framelen > 32
      Case &B00001011
           Rx_bytes_to_load = 64
      #endif
      #if Max_framelen > 64
      Case &B00001100
           Rx_bytes_to_load = 128
      #endif
      #if Max_framelen > 128
      Case &B00001101
           Rx_bytes_to_load = 256
      #endif
      #if Max_framelen > 256
      Case &B00001110
           Rx_bytes_to_load = 512
      #endif
      Case Else
           Rx_bytes_to_load = 0
   End Select

   ' add checksumlength
   Select Case Eee_num
      Case &B00000010
           Rx_bytes_to_load = Rx_bytes_to_load + 1
      Case &B00000011
           Rx_bytes_to_load = Rx_bytes_to_load + 1
      Case &B00000100
           Rx_bytes_to_load = Rx_bytes_to_load + 2
      Case &B00000101
           Rx_bytes_to_load = Rx_bytes_to_load + 4
      Case Else
           ' nix machen
           nop
   End Select

   Rx_bytes_to_load = Rx_bytes_to_load + Ss_num             ' source adress bytes
   Rx_bytes_to_load = Rx_bytes_to_load + Dd_num             ' destination adress bytes
   Rx_bytes_to_load = Rx_bytes_to_load + Pp_num             ' protokoll spec. flag bytes
   Rx_bytes_to_load = Rx_bytes_to_load + 3                  ' Sync, HDB2, HDB1

   ' Auf Adresse prüfen, geht im Moment nur auf 1 und 2 Byte Adresse
   Temp_variable_1 = 3 + Dd_num
   Temp_variable_2 = 3
   Temp_variable_3 = 0
   While Temp_variable_2 < Temp_variable_1
      Incr Temp_variable_2
      Shift Temp_variable_3 , Left , 1
      Temp_variable_3 = Temp_variable_3 + Rx_data(temp_variable_2)
   Wend
   If Temp_variable_3 = Slaveaddress Then
      Slaveaddress_check_flag = 1
   Else
      Slaveaddress_check_flag = 0
   End If


   ' Checksumme prüfen
   Checksum_check_flag = 0
   If Rx_bytes_to_load = Rx_pointer And Slaveaddress_check_flag = 1 Then       ' Frame ist ganz empfangen, Adresse stimmt
      Checksum_var = 0
      Checksum_byte_1 = 0
      Checksum_byte_2 = 0
      Select Case Eee_num
         Case &B00000010                                    ' 8-bit checksum
              Temp_variable_1 = Rx_bytes_to_load - 2
              For Temp_variable_2 = 2 To Temp_variable_1
                  Checksum_var = Checksum_var + Rx_data(temp_variable_2)
              Next
              Checksum_byte_1 = Low(checksum_var)
              If Rx_data(rx_bytes_to_load) = Checksum_byte_1 Then
                  Checksum_check_flag = 1
              Else
                  Checksum_check_flag = 0
              End If
         Case &B00000011                                    ' 8-bit crc
              Temp_variable_1 = Rx_bytes_to_load - 2
              Checksum_byte_1 = Crc8(rx_data(2) , Temp_variable_1)
              If Rx_data(rx_bytes_to_load) = Checksum_byte_1 Then
                  Checksum_check_flag = 1
              Else
                  Checksum_check_flag = 0
              End If
         Case &B00000100                                    ' 16-bit crc
              Temp_variable_1 = Rx_bytes_to_load - 3
              Checksum_var = Crc16(rx_data(2) , Temp_variable_1)
              Checksum_byte_1 = Low(checksum_var)
              Checksum_byte_2 = High(checksum_var)
              Temp_variable_1 = Rx_bytes_to_load - 1
              If Rx_data(rx_bytes_to_load) = Checksum_byte_1 And Rx_data(temp_variable_1) = Checksum_byte_2 Then
                  Checksum_check_flag = 1
              Else
                  Checksum_check_flag = 0
              End If
         Case &B00000101                                    ' 32-bit crc
              Temp_variable_1 = Rx_bytes_to_load - 5
              Checksum_long = Crc32(rx_data(2) , Temp_variable_1)
      End Select
   End If

   ' Frame war komplett, Adresse und Checksumme stimmt
   ' Daten in Datenarray kopieren und Flag setzen
   If Checksum_check_flag = 1 Then                          ' And Aa_num > 0
      Frame_receive_flag = 1                                ' Frame ist komplett und kann in der Mainloop verarbeitet werden


      Temp_variable_1 = 3
      Temp_variable_1 = Temp_variable_1 + Dd_num
      Temp_variable_1 = Temp_variable_1 + Ss_num
      If Pp_num > 0 Then
         Incr Temp_variable_1
         Flag_array(1) = Rx_data(temp_variable_1)
         If Pp_num > 1 Then
            Incr Temp_variable_1
            Flag_array(1) = Rx_data(temp_variable_1)
            If Pp_num > 2 Then
               Incr Temp_variable_1
               Flag_array(1) = Rx_data(temp_variable_1)
            End If
         End If
      End If

      Temp_variable_2 = Temp_variable_1 + Nnnn_num
      Temp_variable_3 = 0
      While Temp_variable_1 < Temp_variable_2
         Incr Temp_variable_1
         Incr Temp_variable_3
         Data_array(temp_variable_3) = Rx_data(temp_variable_1)
      Wend
   End If

   ' Frame gesetzt, acknowledge erzeugen wenn gebraucht
   If Frame_receive_flag = 1 And Aa_num > 0 Then

      Tx_data(1) = &B01010100                               ' Preamble
      Shift Dd_num , Left , 6
      Shift Ss_num , Left , 4
      Shift Pp_num , Left , 2

      If Checksum_check_flag = 1 Then
         Aa_num = &B00000010                                ' Ackn
      Else
         Aa_num = &B00000011                                ' Nack
      End If

      Tx_data(2) = Dd_num
      Tx_data(2) = Tx_data(2) Or Ss_num
      Tx_data(2) = Tx_data(2) Or Pp_num

      Shift Eee_num , Left , 4
      Tx_data(3) = Eee_num
      Tx_data(3) = Tx_data(3) Or Nnnn_num

   End If
End Sub