'-----------------------------------------------------------
' Atmega168 and ENC28J60
'-----------------------------------------------------------
' Version 1.0 - june 2007 by Ben Zijlstra
' august 2007 addins by Viktor Varga

'fusebits:
'Atmega168 - External clock (gaat van 6.25 Mhz naar 12.5 Mhz) No div by 8

$regfile = "m168def.dat"
$crystal = 6250000
$baud = 9600                                                'put terminal on 19200 baud

$hwstack = 64
$swstack = 64
$framesize = 64

$include "enc28j60.inc"

'/* The Ethernet address. */
Const Ethaddr0 = &H43
Const Ethaddr1 = &HC6
Const Ethaddr2 = &HB3
Const Ethaddr3 = &HF3
Const Ethaddr4 = &HAB
Const Ethaddr5 = &H9E

'/* The IP address. */
Const Ipaddr0 = 192
Const Ipaddr1 = 168
Const Ipaddr2 = 2
Const Ipaddr3 = 78

'/* Maximum frame length - The Atmega168 has only 1024 byte internal RAM! */
Const Max_framelen = 200                                    '200 byte will be enough for common tasks


Enc28j60_cs Alias Portb.2
Led Alias Portb.1

Config Enc28j60_cs = Output
Config Led = Output

Set Led                                                     'Turn off the tuxgraphics board LED

Dim X As Byte
Dim A(5) As Byte
Dim Bank As Byte
Dim Enc28j60_data As Byte
Dim Nextpacketptr As Word
Dim Value As Byte
Dim Wdata As Word
Dim Buffer(max_framelen) As Byte
Dim Rstatus As Byte
Dim Length As Word
Dim Rxstat As Word
Dim Tempx As Byte
Dim Ip_id As Word

Declare Sub Enc28j60init
Declare Sub Enc28j60readcontrolregbyte(byval Register As Byte)
Declare Sub Enc28j60writecontrolregbyte(byval Register As Byte , Byval Value As Byte)
Declare Sub Enc28j60selectbank(byval Bank As Byte)
Declare Sub Enc28j60bitfield_set(byval Register As Byte , Byval Value As Byte)
Declare Sub Enc28j60bitfield_clear(byval Register As Byte , Byval Value As Byte)
Declare Sub Enc28j60readphyword(byval Phyregister As Byte)
Declare Sub Enc28j60writephyword(byval Phyregister As Byte , Byval Wdata As Word)
Declare Sub Enc28j60packetsend(byval Pcktlen As Word)
Declare Sub Enc28j60packetreceive
Declare Sub Enc28j60poll
Declare Sub Calcchecksum(byval Startptr As Word , Byval Endptr As Word , Byval Result As Word)
Declare Sub Arpreply
Declare Sub Pingreply
Declare Sub Setip_id
Declare Sub Setst_mac
Declare Sub Setst_ip

'Configuration of the SPI-bus
Config Spi = Hard , Interrupt = Off , Data Order = Msb , Master = Yes , Polarity = Low , Phase = 0 , Clockrate = 4 , Noss = 0

'init the spi pins
Spiinit

Enc28j60_cs = 0
'reset ENC28J60
X = Enc28j60_soft_reset
Spiout X , 1
Enc28j60_cs = 1
Do
Call Enc28j60readcontrolregbyte(estat)
X = Enc28j60_data.estat_clkrdy
Loop Until X = 1

'clock from default divide/4 (6.25 Mhz) to divide/2 (12.5 Mhz)
Call Enc28j60writecontrolregbyte(ecocon , &B00000010)
Waitms 250
Print
Print "Starting Tux"

Call Enc28j60selectbank(3)
'EREVID
A(1) = &B000_10010
Enc28j60_cs = 0
Spiout A(1) , 1
Spiin A(1) , 2
Print "Enc28j60-version = " ; A(2)
Enc28j60_cs = 1

Call Enc28j60init

Do
Call Enc28j60poll
Loop

End

Sub Enc28j60init
   'do bank 0 stuff
   'initialize receive buffer
   '16-bit transfers, must write low byte first
   'set receive buffer start address
   Nextpacketptr = Rxstart_init
   Value = Low(rxstart_init)
   Call Enc28j60writecontrolregbyte(erxstl , Value)
   Value = High(rxstart_init)
   Call Enc28j60writecontrolregbyte(erxsth , Value)
   'set receive pointer address
   Value = Low(rxstart_init)
   Call Enc28j60writecontrolregbyte(erxrdptl , Value)
   Value = High(rxstart_init)
   Call Enc28j60writecontrolregbyte(erxrdpth , Value)
   'set receive buffer end
   Value = Low(rxstop_init)
   Call Enc28j60writecontrolregbyte(erxndl , Value)
   Value = High(rxstop_init)
   Call Enc28j60writecontrolregbyte(erxndh , Value)
   'set transmit buffer start
   Value = Low(txstart_init)
   Call Enc28j60writecontrolregbyte(etxstl , Value)
   Value = High(txstart_init)
   Call Enc28j60writecontrolregbyte(etxsth , Value)
   'do bank 2 stuff
   'enable MAC receive
   Value = 0
   Value.macon1_marxen = 1
   Value.macon1_txpaus = 1
   Value.macon1_rxpaus = 1
   Call Enc28j60writecontrolregbyte(macon1 , Value)
   'bring MAC out of reset
   'enable automatic padding and CRC operations
   Value = 0
   Value.macon3_padcfg0 = 1
   Value.macon3_txcrcen = 1
   Value.macon3_frmlnen = 1
   Call Enc28j60writecontrolregbyte(macon3 , Value)
   'set inter-frame gap (non-back-to-back)
   Call Enc28j60writecontrolregbyte(maipgl , &H12)
   Call Enc28j60writecontrolregbyte(maipgh , &H0C)
   'set inter-frame gap (back-to-back)
   Call Enc28j60writecontrolregbyte(mabbipg , &H12)
   'set the maximum packet size which the controller will accept
   Value = Low(max_framelen)
   Call Enc28j60writecontrolregbyte(mamxfll , Value)
   Value = High(max_framelen)
   Call Enc28j60writecontrolregbyte(mamxflh , Value)

   'bank 3 stuff
   Call Enc28j60writecontrolregbyte(maadr5 , Ethaddr0)
   Call Enc28j60writecontrolregbyte(maadr4 , Ethaddr1)
   Call Enc28j60writecontrolregbyte(maadr3 , Ethaddr2)
   Call Enc28j60writecontrolregbyte(maadr2 , Ethaddr3)
   Call Enc28j60writecontrolregbyte(maadr1 , Ethaddr4)
   Call Enc28j60writecontrolregbyte(maadr0 , Ethaddr5)
   'no loopback of transmitted frames
   Call Enc28j60writephyword(phcon2 , Phcon2_hdldis)
   'switch to bank 0
   Call Enc28j60selectbank(0)
   'enable interrupts
   Value = 0
   Value.eie_intie = 1
   Value.eie_pktie = 1
   Call Enc28j60bitfield_set(eie , Value)

   'Setting receive filters
   Buffer(1) = &HFF : Buffer(2) = &HFF
   Buffer(3) = &HFF : Buffer(4) = &HFF
   Buffer(5) = &HFF : Buffer(6) = &HFF
   Buffer(7) = &H08 : Buffer(8) = &H06
   Buffer(9) = Ipaddr0 : Buffer(10) = Ipaddr1
   Buffer(11) = Ipaddr2 : Buffer(12) = Ipaddr3
   Call Calcchecksum(1 , 11 , 13)                           'Checksum will be in Buffer(13)(14)

   Call Enc28j60writecontrolregbyte(epmcsl , Buffer(14))    'Checksum for ARP packets
   Call Enc28j60writecontrolregbyte(epmcsh , Buffer(13))    'Checksum for ARP packets
   Call Enc28j60writecontrolregbyte(epmm0 , &H3F)           'Pattern Match Mask0 - Broadcast (FF FF FF FF FF FF)
   Call Enc28j60writecontrolregbyte(epmm1 , &H30)           'Pattern Match Mask1 - Packet type (ARP - 08 06)
   Call Enc28j60writecontrolregbyte(epmm4 , &HC0)           'Pattern Match Mask4 - Target IP first 3 byte (ARP packet for us)
   Call Enc28j60writecontrolregbyte(epmm5 , &H03)           'Pattern Match Mask5 - Target IP last 1 byte
   Value = 0
   Value.erxfcon_pmen = 1                                   'Pattern Match enable (ARP only)
   Value.erxfcon_ucen = 1                                   'Unicast enable
   Call Enc28j60bitfield_set(erxfcon , Value)
   Value = 0
   Value.erxfcon_bcen = 1                                   'Broadcast disable
   Call Enc28j60bitfield_clear(erxfcon , Value)
   'CRC check is enabled by default

   'Something is wrong with the Broadcast filter (or the whole theory), it seems
   'like every packet is coming in

   'enable packet reception
   Value = 0
   Value.econ1_rxen = 1
   Call Enc28j60bitfield_set(econ1 , Value)

   'Reset transmit logic
   Value = 0
   Value.econ1_txrst = 1
   Call Enc28j60bitfield_set(econ1 , Value)
   Call Enc28j60bitfield_clear(econ1 , Value)

End Sub


Sub Enc28j60selectbank(bank As Byte)
'get ECON1 (BSEL1 en BSEL0)
A(1) = &B000_11111
Enc28j60_cs = 0
Spiout A(1) , 1
Spiin A(1) , 2
Enc28j60_cs = 1
A(2) = A(2) And &B1111_1100                                 'strip bank part
A(2) = A(2) Or Bank
A(1) = &B010_11111
Enc28j60_cs = 0
Spiout A(1) , 2
Enc28j60_cs = 1
End Sub


Sub Enc28j60writecontrolregbyte(register As Byte , Value As Byte)
Bank = 0
If Register.7 = 1 Then Bank = 2
If Register.6 = 1 Then Bank = Bank + 1
Register = Register And &B00011111
Call Enc28j60selectbank(bank)
Register.6 = 1                                              'to get a 010_register
A(1) = Register
A(2) = Value
Enc28j60_cs = 0
Spiout A(1) , 2
Enc28j60_cs = 1
End Sub


Sub Enc28j60readcontrolregbyte(register As Byte)
Local Mcphy As Byte
Bank = 0
Mcphy = 0
If Register.7 = 1 Then Bank = 2
If Register.6 = 1 Then Bank = Bank + 1
If Register.5 = 1 Then Mcphy = 1
Register = Register And &B00011111
Call Enc28j60selectbank(bank)
A(1) = Register
Enc28j60_cs = 0
Spiout A(1) , 1
Spiin A(1) , 3
Enc28j60_cs = 1
'Depending of register (E, MAC, MII) yes or no dummybyte
If Mcphy = 1 Then
   Enc28j60_data = A(2)
   Else
   Enc28j60_data = A(3)
End If
End Sub


Sub Enc28j60bitfield_set(register As Byte , Value As Byte)
Bank = 0
If Register.7 = 1 Then Bank = 2
If Register.6 = 1 Then Bank = Bank + 1
Register = Register And &B00011111
Call Enc28j60selectbank(bank)
Register = Register Or &B100_00000
A(1) = Register
A(2) = Value
Enc28j60_cs = 0
Spiout A(1) , 2
Enc28j60_cs = 1
End Sub


Sub Enc28j60bitfield_clear(register As Byte , Value As Byte)
Bank = 0
If Register.7 = 1 Then Bank = 2
If Register.6 = 1 Then Bank = Bank + 1
Register = Register And &B00011111
Call Enc28j60selectbank(bank)
Register = Register Or &B101_00000
A(1) = Register
A(2) = Value
Enc28j60_cs = 0
Spiout A(1) , 2
Enc28j60_cs = 1
End Sub


Sub Enc28j60readphyword(phyregister As Byte)
'set the right address and start the register read operation
Call Enc28j60writecontrolregbyte(miregadr , Phyregister)
Call Enc28j60writecontrolregbyte(micmd , Micmd_miird)
'wait until the PHY read complets
Do
Call Enc28j60readcontrolregbyte(mistat)
Loop Until Enc28j60_data.mistat_busy = 0
'quit reading
Call Enc28j60writecontrolregbyte(micmd , 0)
'get data value
Call Enc28j60readcontrolregbyte(mirdl)
Wdata = Enc28j60_data
Shift Wdata , Left , 8
Call Enc28j60readcontrolregbyte(mirdh)
Wdata = Wdata + Enc28j60_data
End Sub


Sub Enc28j60writephyword(phyregister As Byte , Wdata As Word)
Call Enc28j60readphyword(phyregister)
Local Temp As Byte
'set the PHY register address
Call Enc28j60writecontrolregbyte(miregadr , Phyregister)
Call Enc28j60readcontrolregbyte(miregadr)
Temp = Miregadr
Value = Low(wdata)
Call Enc28j60writecontrolregbyte(miwrl , Value)
Value = High(wdata)
Call Enc28j60writecontrolregbyte(miwrh , Value)
Do
Call Enc28j60readcontrolregbyte(mistat)
Loop Until Enc28j60_data.mistat_busy = 0
End Sub

Sub Enc28j60poll
Call Enc28j60readcontrolregbyte(epktcnt)
If Enc28j60_data > 0 Then
   Call Enc28j60packetreceive
End If
End Sub


Sub Enc28j60packetreceive
   Reset Led
   Print "EPKTCNT = " ; Bin(enc28j60_data)
   Local Wtemp As Word
   'set the read pointer to the start of the received packet
   Value = Low(nextpacketptr)
   Call Enc28j60writecontrolregbyte(erdptl , Value)
   Value = High(nextpacketptr)
   Call Enc28j60writecontrolregbyte(erdpth , Value)
   Print "Present nextpacketpntr " ; Hex(nextpacketptr)


    Enc28j60_cs = 0
    'Send Read Buffer Memory command
    Spdr = &H3A
    Do
    Loop Until Spsr.spif = 1

    'Get the first 6 byte (3 word: Nextpacketptr, Packetlength, Rxstat)
    For X = 1 To 6
          Spdr = &HFF                                       'SPI read
          Do
          Loop Until Spsr.spif = 1                          'SPI ready
          Buffer(x) = Spdr
    Next X

    Nextpacketptr = Buffer(2) * 256
    Nextpacketptr = Nextpacketptr + Buffer(1)
    Length = Buffer(4) * 256
    Length = Length + Buffer(3)
    Rxstat = Buffer(6) * 256
    Rxstat = Rxstat + Buffer(5)

    Print "New Nextpacketpntr " ; Hex(nextpacketptr)
    Print "Packetlength = " ; Hex(length)
    Print "Rxstat = " ; Bin(rxstat)

    'Get the payload
    Length = Length - 4                                     'Discard CRC
    For X = 1 To Length
          Spdr = &HFF                                       'SPI read
          Do
          Loop Until Spsr.spif = 1                          'SPI ready
          Buffer(x) = Spdr
    Next X

    Enc28j60_cs = 1


   'move the rx read pointer to the start of the next received packet
   'this frees the memory we just read out
   Value = Low(nextpacketptr)
   Call Enc28j60writecontrolregbyte(erxrdptl , Value)
   Value = High(nextpacketptr)
   Call Enc28j60writecontrolregbyte(erxrdpth , Value)
   'decrement the packet counter indicate we are done with this packet
   Value = 0
   Value.econ2_pktdec = 1
   Call Enc28j60bitfield_set(econ2 , Value)
   Set Led

   'Print the packet content
    Print "The packet:"
    For X = 1 To Length
        Print Hex(buffer(x)) ; "  " ;
    Next X
    Print

    'Handle the packet
    If Buffer(13) = &H08 Then
      If Buffer(14) = &H06 Then                             'Type:ARP
         If Buffer(21) = &H00 Then                          'ARP request
            If Buffer(22) = &H01 Then                       'ARP request
              If Buffer(39) = Ipaddr0 Then                  'ARP for us
                If Buffer(40) = Ipaddr1 Then
                   If Buffer(41) = Ipaddr2 Then
                      If Buffer(42) = Ipaddr3 Then
                        Call Arpreply
                      End If
                   End If
                End If
              End If
            End If
         End If
      End If
      If Buffer(14) = &H00 Then                             'Type:IP
         If Buffer(15) = &H45 Then                          'We handle only simple IP packets
            If Buffer(21) = 0 Then                          'We handle only non fragmented packets
              If Buffer(31) = Ipaddr0 Then                  'Ip packet for us
                If Buffer(32) = Ipaddr1 Then
                   If Buffer(33) = Ipaddr2 Then
                      If Buffer(34) = Ipaddr3 Then
                        If Buffer(24) = 1 Then                       'Protocol:ICMP
                           If Buffer(35) = &H08 Then                 'ICMP echo request
                              Call Pingreply
                           End If
                        End If
                        If Buffer(24) = 17 Then                      'Protocol:UDP
                        End If
                        If Buffer(24) = 6 Then                       'Protocol:TCP
                        End If
                      End If
                   End If
                End If
              End If
            End If
         End If
      End If

    End If




End Sub


Sub Enc28j60packetsend(pcktlen As Word)
   'Load packet into the ENC
   Enc28j60_cs = 0
   Spdr = Enc28j60_write_buf_mem
   Do
   Loop Until Spsr.spif = 1
   Spdr = &B000_1110                                        'per packet byte
   Do
   Loop Until Spsr.spif = 1
   For X = 1 To Pcktlen
      Spdr = Buffer(x)
      Do
      Loop Until Spsr.spif = 1
   Next X
   Enc28j60_cs = 1

   'Minimum packet length is 60
   If Pcktlen < 60 Then Pcktlen = 60

   'Reset transmit logic
   Value = 0
   Value.econ1_txrst = 1
   Call Enc28j60bitfield_set(econ1 , Value)
   Call Enc28j60bitfield_clear(econ1 , Value)
   'set the write pointer to start of transmit buffer area
   Value = Low(txstart_init)
   Call Enc28j60writecontrolregbyte(ewrptl , Value)
   Value = High(txstart_init)
   Call Enc28j60writecontrolregbyte(ewrpth , Value)
   'set the TXND pointer to correspond to the packet size given
   Value = Low(txstart_init)
   Value = Value + Low(pcktlen)
   Call Enc28j60writecontrolregbyte(etxndl , Value)
   Value = High(txstart_init)
   Value = Value + High(pcktlen)
   Call Enc28j60writecontrolregbyte(etxndh , Value)
   'write per-packet control byte has been put in the writeroutine
   'send the contents of the transmit buffer onto the network
   Value = 0
   Value.econ1_txrts = 1
   Call Enc28j60bitfield_set(econ1 , Value)
End Sub

Sub Calcchecksum(startptr As Word , Endptr As Word , Result As Word)
  Local I As Word
  Local Tmp As Word
  Local Sum As Long
  Sum = 0
  For I = Startptr To Endptr Step 2
      Sum = Sum + Buffer(i + 1)
      Tmp = Buffer(i) * 256
      Sum = Sum + Tmp
  Next I
  I = Highw(sum)
  Tmp = Sum
  Tmp = Tmp + I
  Tmp = Not Tmp
  Buffer(result) = High(tmp)
  Buffer(result + 1) = Low(tmp)
End Sub

Sub Arpreply
   'The original request packet is in the buffer, we just change some things

   Local I As Byte

   'Swap MAC addresses
   Call Setst_mac

   'Copy target MAC in ARP packet - starting at pos 33, copy from pos 1
   For I = 1 To 6
      Buffer(32 + I) = Buffer(i)
   Next I
   'Set target IP in ARP packet - starting at pos 39, original starting at pos 29
   For I = 1 To 4
      Buffer(38 + I) = Buffer(28 + I)
   Next I

   'Copy source MAC to ARP packet pos 23 from pos 7
   For I = 1 To 6
      Buffer(22 + I) = Buffer(6 + I)
   Next I
   'Set source IP to ARP packet pos 29
   Buffer(29) = Ipaddr0
   Buffer(30) = Ipaddr1
   Buffer(31) = Ipaddr2
   Buffer(32) = Ipaddr3

   'Set ARP type from Request to Reply
   Buffer(22) = 2

   'Send the reply packet
   Call Enc28j60packetsend(42)

End Sub

Sub Pingreply
   'The original request packet is in the buffer, we just change some things
   Local I As Byte
   Local Packetlength As Word

   'Swap MAC addresses
   Call Setst_mac

   'Set IP ID field
   Call Setip_id

   'Swap IP addresses
   Call Setst_ip

   'Zero out original IP checksum fields
   Buffer(25) = 0
   Buffer(26) = 0
   'Calc new IP checksum
   Call Calcchecksum(15 , 33 , 25)

   'Set ICMP type to Echo reply
   Buffer(35) = 0
   'Zero out original ICPM checksum fields
   Buffer(37) = 0
   Buffer(38) = 0
   'Calc new ICPM checksum, length calculated from IP packet length
   Packetlength = Buffer(17) * 256
   Packetlength = Packetlength + Buffer(18)
   Packetlength = Packetlength + 13                         'We are going to calculate the checksum till the end of packet (IP length + 14 byte of the ethernet stuff), -1 to get word start
   Call Calcchecksum(35 , Packetlength , 37)

   'Setting packetlength to the correct value
   Packetlength = Packetlength + 1

   'Send the reply packet
   Call Enc28j60packetsend(packetlength)

End Sub

Sub Setip_id
   Buffer(19) = High(ip_id)
   Buffer(20) = Low(ip_id)
   Ip_id = Ip_id + 1
End Sub

Sub Setst_mac
   Local I As Byte
   'Set target MAC in ethernet frame - starting at pos 1, original starting at pos 7
   For I = 1 To 6
      Buffer(i) = Buffer(6 + I)
   Next I
   'Set source MAC in ethernet frame, pos 7
   Buffer(7) = Ethaddr0
   Buffer(8) = Ethaddr1
   Buffer(9) = Ethaddr2
   Buffer(10) = Ethaddr3
   Buffer(11) = Ethaddr4
   Buffer(12) = Ethaddr5
End Sub

Sub Setst_ip
   Local I As Byte
   'Set target IP in IP header - starting at pos 31, original starting at pos 27
   For I = 1 To 4
      Buffer(30 + I) = Buffer(26 + I)
   Next I
   'Set source IP in IP header, pos 27
   Buffer(27) = Ipaddr0
   Buffer(28) = Ipaddr1
   Buffer(29) = Ipaddr2
   Buffer(30) = Ipaddr3
End Sub