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 Robotics / NXT / 694
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Subject: 
Re: Difficulty with WRITE COMMAND over BT
Newsgroups: 
lugnet.robotics.nxt
Date: 
Fri, 27 Apr 2007 12:50:55 GMT
Viewed: 
26138 times
  
In lugnet.robotics.nxt, Pavel Petrovic wrote:
> - however, if I try to download a real .rxe file that was produced using NBC
> compiler (and this .rxe file can be downloaded normally using NBC utility and
> runs on NXT correctly otherwise), then writing to file works until the last 72
> or so characters are to be downloaded. At that time, the WRITE COMMAND simply
> does not respond with a reply packet as it should. It happens no matter how
> big/small chunks I use to send the data to NXT over bloodytooth (and they are
> always less then 64 bytes - the packet limit size).

It's hard to say what exactly might be going wrong.  Here's how I write a file
to the NXT:

    // write in < 64 byte chunks
    xferred := 0;
    aStream.Position := 0; // start at the beginning
    while xferred < size do
    begin
      cnt := Min(size - xferred, kNXT_MaxBytes-3);
      // fill our buffer with the right number of bytes
      for i := 0 to cnt - 1 do
        aStream.Read(buf.Data[i], 1);
      // write these bytes to the NXT
      Result := NXTWrite(handle, buf, cnt, cnt = (size - xferred));
      if not Result then Break;
      inc(xferred, cnt);
    end;

The maximum number of bytes per write is 61 (64-3).  Each command is sent with
the no response flag set (0x81 rather than 0x81) except for the very last
command (when cnt = (size - xferred)).

John Hansen



Message has 1 Reply:
  Re: Difficulty with WRITE COMMAND over BT
 
(...) Thank you very much for the reply. It is still consistently puzzling. If I write some other file - for example a text file named file.txt, I can write and close, and see it in the list (through findfirst/findnext) successfully. This works both (...) (19 years ago, 28-Apr-07, to lugnet.robotics.nxt)

Message is in Reply To:
  Difficulty with WRITE COMMAND over BT
 
Hi, I am attempting to download a .rxe program file to NXT from some programming environment that allows communicating over serial port. So I connect to NXT (with 1.04 firmware) from the WinXPSP2 box with BT USB dongle, and use the commands (...) (19 years ago, 26-Apr-07, to lugnet.robotics.nxt)

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