READ_HEX_File_Format.txt

Example :

:1005AA00000102030405060708090A0B0C0D0E0F88
^----------- use for calculate check sum ----------^^^
|_|
Check sum__|
RECLEN = 0x10 = 16
ADDRESS = 0x05AA
RECTYPE = 00
DATA = 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
CHKSUM = 0x88 = 256 -sum(0x00+..+0x0F)= 256- 0x78














type buffer=array of byte;  //assign as Dynamic array
var HexBuf:buffer;

function readline(HexLine:string; var Buf:buffer):integer;
var ADDR,count:integer;
 CHKSUM,SUMLINE,RECLEN,RECTYPE,DATA:byte;
 t:shortstring;
begin
 // Array length may be change, here is 100,000
 SetLength(HexBuf,100000);
 if HexLine[1]=':' then begin
  t:='$'+copy(HexLine,2,2);   // get length
  RECLEN:=strtoint(t);
  CHKSUM:=0;
  CHKSUM:=CHKSUM+RECLEN;
  t:='$'+copy(HexLine,4,4); // get address
  ADDR:=strtoint(t);
  CHKSUM:=CHKSUM+lo(ADDR)+hi(ADDR);
  t:='$'+copy(HexLine,8,2);
  RECTYPE:=strtoint(t);
  CHKSUM:=CHKSUM+RECTYPE;
  case RECTYPE of
   0:begin             // datablock
     count:=0;
     while (count < RECLEN) do begin
      t:='$'+copy(HexLine,10+2*count,2);
      DATA:=strtoint(t);
      CHKSUM:=CHKSUM+DATA;
      Buf[ADDR+count]:=DATA;
      inc(count);
     end;
     t:='$'+copy(HexLine,10+2*count,2);
     SUMLINE:=strtoint(t);
     end;
   1:begin			// end of file
      t:='$'+copy(HexLine,10,2);
      SUMLINE:=strtoint(t);
      result:=1;
     end;
     else
     begin
        result := -2;  // invalid record type
        exit;
     end;
    end; //case
  // test checksum
  DATA:=SUMLINE+CHKSUM;
  if (DATA<>0) then result:=-3; // checksum error
 end
 else result:=-1; // no record
end;




To use this routine

Here is an example demonstration how to use the above readline routine

procedure TForm1.Button1Click(Sender: TObject);
var Fname,line:string;
    Fp : textfile;
    ErrorCode:integer;
begin
    Fname:='test.hex';
    AssignFile(Fp,Fname); { File selected in dialog }
    Reset(Fp);
    while not eof(Fp) do
    begin
      Readln(Fp, line);{ Read first line of file }
      ErrorCode := readline(line,HexBuf);
      if (ErrorCode=0) then
      begin
       // Do some thing if read one line OK
       // such send data to serial port,parallel port etc.
      end
      else
      begin
       // Error handle here
       //  0 = No error
       // -1 = File not Intel Hex format
       // -2 = Invalid record type
       // -3 = Checksum error
       break;  // exit while loop
      end;
    end;
    CloseFile(Fp);
end;