'---------------------------------------------------------------- ' (c) 1995-2009, MCS ' Bootloader.bas ' This sample demonstrates how you can write your own bootloader ' in BASCOM BASIC ' VERSION 2 of the BOOTLOADER. The waiting for the NAK is stretched ' further a bug was resolved for the M64/M128 that have a big page size '----------------------------------------------------------------- 'This sample will be extended to support other chips with bootloader 'The loader is supported from the IDE $crystal = 16000000 $baud = 57600 'this loader uses serial com 'It is VERY IMPORTANT that the baud rate matches the one of the boot loader 'do not try to use buffered com as we can not use interrupts 'possible return codes of the PC bootloader.exe ' -6005 Cancel requested ' -6006 Fatal time out ' -6007 Unrecoverable event during protocol ' -6008 Too many errors during protocol ' -6009 Block sequence error in Xmodem ' -6016 Session aborted $regfile = "m128def.dat" Const Loaderchip = 128 #if Loaderchip = 128 ' Mega128 $loader = &HFC00 ' 1024 words Const Maxwordbit = 7 'Z7 is maximum bit ' Config Com1 = Dummy , Synchrone = 0 , Parity = None , Stopbits = 1 , Databits = 8 , Clockpol = 0 #endif 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 , 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 Dim Bkind As Byte , Bstarted As Byte Disable Interrupts 'we do not use ints 'Waitms 100 'wait 100 msec sec 'We start with receiving a file. The PC must send this binary file 'some constants used in serial com Const Nak = &H15 Const Ack = &H06 Const Can = &H18 $timeout = 200000 '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 'we try 5 times Testfor123: Bstatus = Waitkey() 'wait for the loader to send a byte #if Cdebug Print "Got " #endif Print Chr(bstatus); If Bstatus = 123 Then 'did we received value 123 ? Bkind = 0 'normal flash loader Goto Loader Elseif Bstatus = 124 Then ' EEPROM Bkind = 1 ' EEPROM loader Goto Loader Elseif Bstatus <> 0 Then Decr Bretries If Bretries <> 0 Then Goto Testfor123 'we test again End If #if Cdebug Print "RESET" #endif Goto _reset 'goto the normal reset vector at address 0 'this is the loader routine. It is a Xmodem-checksum reception routine Loader: #if Cdebug Print "Clear buffer" #endif Do Bstatus = Waitkey() Loop Until Bstatus = 0 If Bkind = 0 Then Spmcrval = 3 : Gosub Do_spm ' erase the first page Spmcrval = 17 : Gosub Do_spm ' re-enable page End If Bretries = 10 'number of retries Do Bblocklocal = 1 Bstarted = 0 ' we were not started yet Csum = 0 'checksum is 0 when we start Print Chr(nak); ' firt time send a nack Do Bstatus = Waitkey() 'wait for statuse byte Select Case Bstatus Case 1: ' start of heading, PC is ready to send Csum = 1 'checksum is 1 Bblock = Waitkey() : Csum = Csum + Bblock 'get block Bcsum1 = Waitkey() : Csum = Csum + Bcsum1 'get checksum first byte For J = 1 To 128 'get 128 bytes Buf(j) = Waitkey() : Csum = Csum + Buf(j) Next Bcsum2 = Waitkey() '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 Chr(ack); 'acknowledge Incr Bblocklocal 'increase local block count ???????? Else 'no match so send nak Print Chr(nak); End If Else Print Chr(nak); 'blocks do not match End If Case 4: ' end of transmission , file is transmitted If Wrd > 0 And Bkind = 0 Then 'if there was something left in the page Wrd = 0 'Z pointer needs wrd to be 0 Spmcrval = 5 : Gosub Do_spm 'write page Spmcrval = 17 : Gosub Do_spm ' re-enable page End If ' Waitms 100 ' OPTIONAL REMARK THIS IF THE DTR SIGNAL ARRIVES TO EARLY Print Chr(ack); ' send ack and ready Waitms 20 Goto _reset ' start new program Case &H18: ' PC aborts transmission Goto _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 _reset 'reset chip End If Loop 'write one or more pages Writepage: If Bkind = 0 Then 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 lds r0, {vl} 'store them into r0 and r1 registers lds r1, {vh} Spmcrval = 1 : 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 = 5 : Gosub Do_spm 'write page Spmcrval = 17 : Gosub Do_spm ' re-enable page Page = Page + 1 'next page Spmcrval = 3 : Gosub Do_spm ' erase next page Spmcrval = 17 : Gosub Do_spm ' re-enable page End If Next Else 'eeprom For J = 1 To 128 Writeeeprom Buf(j) , Wrd Wrd = Wrd + 1 Next End If 'Toggle Portb.2 : Waitms 10 : Toggle Portb.2 'indication that we write Return Do_spm: Bitwait Spmcsr.0 , Reset ' check for previous SPM complete Bitwait Eecr.1 , Reset 'wait for eeprom 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} #if(loaderchip = 128) ' #if _romsize > 65536 lds r24,{Z+2} sts rampz,r24 ' we need to set rampz also for the M128 #endif Spmcsr = Spmcrval 'assign register spm 'this is an asm instruction nop nop Return 'How you need to use this program: '1- compile this program '2- program into chip with sample elctronics programmer '3- select MCS Bootloader from programmers '4- compile a new program for example M88.bas '5- press F4 and reset your micro ' the program will now be uploaded into the chip with Xmodem Checksum ' you can write your own loader.too 'A stand alone command line loader is also available 'How to call the bootloader from your program without a reset ??? 'Do ' Print "test" ' Waitms 1000 ' If Inkey() = 27 Then ' Print "boot" ' Goto &H1C00 ' End If 'Loop 'The GOTO will do the work, you need to specify the correct bootloader address 'this is the same as the $LOADER statement.