Hallo darwin.nuernberg,
die Leute im 2. Link meinen was anderes.
Hier mal ein kleines Beispiel, habe ich mal im Web gefunden:
Ich hoffe, Du kannst es gebrauchen.Code:'
' -----[ 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 |
' +-----------------+-----------------+
'
'
$regfile = "m128def.dat"
$crystal = 16000000
$baud = 19200
$hwstack = 128
$swstack = 128
$framesize = 128
' -----[ Constants ]--------------------------------------------------
'
Const Preamble_x = &B01010101 ' Preamble byte
Const Sbyte_x = &B01010100 ' Synchronisation byte
Const Crcpoly = &H1021 ' CRC-CCITT
Const Hdb2_x = &H52
Const Hdb1_x = &H48
Const Myaddress = 123 ' Node - Adresse
' -----[ Variables ]--------------------------------------------------
'
Dim Preamble As Byte ' Preamble byte
Dim Sbyte As Byte ' Sync byte
Dim Crc As Word ' CRC Word
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 Temp1 As Byte ' Temporäre Variable
Dim Temp2 As Byte ' Temporäre Variable
Dim Tmpw1 As Word
Dim Tmpw2 As Word
Dim I As Integer
Dim Ausgabe As String * 8
Dim Dummy As String * 1
' -----[ Initialization ]---------------------------------------------
'
Config Portg = Output ' Portb ist output
'Portb = &HFF
Preamble = Preamble_x
Sbyte = Sbyte_x
Ausgabe = " 123.5"
'------[ Program ]----------------------------------------------------
'
Sound Portg.0 , 15000 , 15
_start:
'Temp1 = Waitkey() ' Warten auf Daten
Temp1 = Inkey()
' Ist das empf. Zeichen das SYNC byte dann die nächsten 8 Byte
' vom Master lesen, sonst zurück zum Start
If Temp1 <> Sbyte Then
'Portg.1 = 1 ' Irgendwas empfangen
'Printbin Temp1
Goto _start
Else
' Get packet in binary mode
Inputbin Hdb2 , Hdb1 , Dab1 , Sab1 , Db8 , Db7 , Db6 , Db5 , Db4 , Db3 , Db2 , Db1 , Crc2 , Crc1
Portg.2 = 1 ' Packet empfangen
' Packet header check routine
'
' Check HDB2 to see if MCU are capable to use the packet
' structure, if not goto Start
If Hdb2 <> Hdb2_x Then Goto _start
' Check HDB1 to see if MCu are capable to use the packet
' structure, if not goto Start
If Hdb1 <> Hdb1_x Then Goto _start
' Address check routine
'
' Check if this is the node addressed, if not goto Start
If Dab1 <> Myaddress Then Goto _start
' Check CRC for all the received bytes
Gosub Check_crc
' Check if there was any CRC errors, if so send NAK
If Crc <> 0 Then Goto Nak
' No CRC errors in packet so check what to do.
'
' Associated Function (place it between +++ lines)
'+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
' Portb = Db1
Sound Portg.0 , 10000 , 10 'BEEP
If Db1 = 255 Then
Portg.1 = 1
Else
Portg.1 = 0
End If
Dummy = Mid(ausgabe , 1 , 1)
Db1 = Asc(dummy)
Dummy = Mid(ausgabe , 2 , 1)
Db2 = Asc(dummy)
Dummy = Mid(ausgabe , 3 , 1)
Db3 = Asc(dummy)
Dummy = Mid(ausgabe , 4 , 1)
Db4 = Asc(dummy)
Dummy = Mid(ausgabe , 5 , 1)
Db5 = Asc(dummy)
Dummy = Mid(ausgabe , 6 , 1)
Db6 = Asc(dummy)
Dummy = Mid(ausgabe , 7 , 1)
Db7 = Asc(dummy)
Dummy = Mid(ausgabe , 8 , 1)
Db8 = Asc(dummy)
'+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
'
Ack_:
' Send ACK (i.e tell master that packet was OK)
' Set ACKs bit in HDB2 (xxxxxx10)
Hdb2 = Hdb2 Or &B00000010
Hdb2 = Hdb2 And &B11111110
Goto Send
Nak:
' Send NAK (i.e tell master that packet was bad)
' Set ACK bits in HDB2 (xxxxxx11)
Hdb2 = Hdb2 Or &B00000011
Goto Send
Send:
' Swap SAB1 <-> DAB1 address bytes
Temp2 = Sab1
Sab1 = Dab1
Dab1 = Temp2
' Clear CRC variable
Crc = 0
' Put HDB2 in variable Tmp_Byte1
Temp1 = Hdb2
' Calculate CRC
Gosub Calc_crc
' Put HDB1 in variable Tmp_Byte1
Temp1 = Hdb1
' Calculate CRC
Gosub Calc_crc
' Put DAB1 in variable Tmp_Byte1
Temp1 = Dab1
' Calculate CRC
Gosub Calc_crc
' Put SAB1 in variable Tmp_Byte1
Temp1 = Sab1
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 8
Temp1 = Db8
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 7
Temp1 = Db7
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 6
Temp1 = Db6
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 5
Temp1 = Db5
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 4
Temp1 = Db4
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 3
Temp1 = Db3
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 2
Temp1 = Db2
' Calculate CRC
Gosub Calc_crc
' Put Data in variable Tmp_Byte 1
Temp1 = Db1
' Calculate CRC
Gosub Calc_crc
' Move calculated Hi_CRC value to outgoing packet
Crc2 = High(crc)
' Move calculated Lo_CRC value to outgoing packet
Crc1 = Low(crc)
' Send packet to master, including the preamble and SYNC byte
' Print "Antwort"
Printbin Preamble ; Sbyte_x ; Hdb2 ; Hdb1 ; Dab1 ; Sab1
Printbin Db8 ; Db7 ; Db6 ; Db5 ; Db4 ; Db3 ; Db2 ; Db1
Printbin Crc2 ; Crc1
' Print "Ende"
' Give AVR time to shift out all bits before setting to Rx
Waitms 50
' Done, go back to Start and wait for a new packet
Goto _start
End If
' -----[ Subroutines ]------------------------------------------------
'
'Soubroutine for checking all received bytes in packet
Check_crc:
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
Return
' 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
mfg
AVRWalli
