$crystal = 32000000                               ' xmega32e5 is running on 32 MHz
$regfile = "xm32E5def.dat"
$hwstack = 40
$swstack = 40
$framesize = 40
'first enabled the osc of your choice
Config Osc = Enabled , 32mhzosc = Enabled                   'internal 2 MHz and 32 MHz enabled

'configure the systemclock
Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1       ' we will use 32 MHz and divide by 1 to end up with 32 MHz

$loader = &H4000                                            ' bootloader starts after the application

'this sample uses 38400 baud. To be able to use the Xplain which has a bootloader working at 9600 baud you need to use 9600 baud
Config Com1 = 115200 , Mode = Asynchroneous , Parity = None , Stopbits = 1 , Databits = 8       ' use USART C0
'COM0-USARTC0, COM1-USARTC2, COM2-USARTD0. etc.

Open "COM1:" For Binary As #1



Const Maxwordbit = 6                                        ' Z7 is maximum bit                                   '
Const Maxword =(2 ^ Maxwordbit) * 2               '128
Const Maxwordshift = Maxwordbit + 1
Const Cdebug = 0                                  ' leave this to 0


'Dim the used variables
Dim Bstatus As Byte , Bretries As Byte , Bmincount As Byte , Bblock As Byte , Bblocklocal As Byte
Dim Bcsum1 As Byte , Bcsum2 As Byte , Buf(128) As Byte , Csum As Byte
Dim J As Byte , Spmcrval As Byte                  ' self program command byte value

Dim Z As Long                                     'this is the Z pointer word
Dim Vl As Byte , Vh As Byte                                 ' these bytes are used for the data values
Dim Wrd As Word , Page As Word                    'these vars contain the page and word address


Disable Interrupts                                'we do not use ints
Rampz = 0
'We start with receiving a file. The PC must send this binary file

'some constants used in serial com
Const Cnak = &H15
Const Cack = &H06
Const Ccan = &H18


$timeout = 16000000                                           'we use a timeout
'When you get LOADER errors during the upload, increase the timeout value
'for example at 16 Mhz, use 200000


Bretries = 5 : Bmincount = 3                      'we try 10 times and want to get 123 at least 3 times
Do
   Bstatus = Waitkey(#1)                                    'wait for the loader to send a byte

   If Bstatus = 123 Then                           'did we received value 123 ?
      If Bmincount > 0 Then
         Decr Bmincount
      Else
         Print #1 , Chr(bstatus);
         Goto Loader                                        ' yes so run bootloader
      End If
   Else                                                      'we received some other data
      If Bretries > 0 Then                                   'retries left?
         Bmincount = 3
         Decr Bretries
      Else
         Goto Proces_reset                                   'goto the normal reset vector at address 0
      End If
   End If
Loop




'this is the loader routine. It is a Xmodem-checksum reception routine
Loader:
   Do
      Bstatus = Waitkey(#1)
   Loop Until Bstatus = 0
'   Spmcrval = &H20 : Gosub Do_spm                           ' erase  all app pages
'^^^^^^^ THIS LINE REMARKED
   Bretries = 10                                            'number of retries

   Do
      Csum = 0                                              'checksum is 0 when we start
      Bblocklocal = 1

      Print #1 , Chr(cnak);                                 ' firt time send a nack
      Do

         Bstatus = Waitkey(#1)                              'wait for statuse byte

         Select Case Bstatus
            Case 1:                                         ' start of heading, PC is ready to send
               Csum = 1                                     'checksum is 1
               Bblock = Waitkey(#1) : Csum = Csum + Bblock  'get block
               Bcsum1 = Waitkey(#1) : Csum = Csum + Bcsum1  'get checksum first byte
               For J = 1 To 128                             'get 128 bytes
                  Buf(j) = Waitkey(#1) : Csum = Csum + Buf(j)
               Next
               Bcsum2 = Waitkey(#1)                         'get second checksum byte

               If Bblocklocal = Bblock Then          'are the blocks the same?

                  If Bcsum2 = Csum Then                     'is the checksum the same?
                     Gosub Writepage                        'yes go write the page
                     Print #1 , Chr(cack);                  'acknowledge
                     Incr Bblocklocal                       'increase local block count
                  Else                                         'no match so send nak
                     Print #1 , Chr(cnak);
                  End If
               Else
                  Print #1 , Chr(cnak);                     'blocks do not match
               End If
            Case 4:                                    ' end of transmission , file is transmitted
               If Wrd > 0 Then                      'if there was something left in the page
                  Wrd = 0                          'Z pointer needs wrd to be 0
                  Spmcrval = &H25 : Gosub Do_spm            'write page
                  '^^^^^USE THE NEW ERASE AND PROGRAM COMMAND
               End If
               Print #1 , Chr(cack);                        ' send ack and ready
               Waitms 20
               Goto Proces_reset
            Case &H18:                                      ' PC aborts transmission
               Goto Proces_reset                            ' ready
            Case 123 : Exit Do                         'was probably still in the buffer
            Case 124 : Exit Do
            Case Else
               Exit Do                                 ' no valid data
         End Select
      Loop
      If Bretries > 0 Then                            'attempte left?
         Waitms 1000
         Decr Bretries                                          'decrease attempts
      Else
         Goto Proces_reset                            'reset chip
      End If
   Loop



'write one or more pages
Writepage:
   For J = 1 To 128 Step 2                        'we write 2 bytes into a page
      Vl = Buf(j) : Vh = Buf(j + 1)               'get Low and High bytes
      R0 = Vl                                               'store them into r0 and r1 registers
      R1 = Vh
      Spmcrval = &H23 : Gosub Do_spm                        'write value into page at word address
      Wrd = Wrd + 2                                         ' word address increases with 2 because LS bit of Z is not used
      If Wrd = Maxword Then                                 ' page is full
         Wrd = 0                                            'Z pointer needs wrd to be 0
         Spmcrval = &H25 : Gosub Do_spm                     'write page
         '^^^^^USE THE NEW ERASE AND PROGRAM COMMAND
         Page = Page + 1                                    'next page
      End If
   Next
Return


Do_spm:
   Z = Page                                        'make equal to page
   Shift Z , Left , Maxwordshift                   'shift to proper place
   Z = Z + Wrd                                     'add word
   ! lds r30,{Z}
   ! lds r31,{Z+1}

   Nvm_cmd = Spmcrval
   Cpu_ccp = &H9D
   ! spm                                                    'this is an asm instruction
Do_spm_busy:
   ! lds r23, NVM_STATUS
   ! sbrc r23,7 ;if  busy bit is cleared  skip next instruc tion
   ! rjmp do_spm_busy
Return



Proces_reset:
   Rampz = 0
   Print #1 , "RST"
   Goto _reset                                              'start at address 0

 

         Print #1 , Chr(bstatus);
         Goto Loader                                        ' yes so run bootloader