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Subject: 
RE: The pain of communicating with the RCX
Newsgroups: 
lugnet.robotics.rcx.pbforth
Date: 
Fri, 10 Mar 2000 15:38:09 GMT
Viewed: 
1812 times
  
ernst wrote:

Uploading srec files has been without problem for me; it's uploading text
that's painful. Does your program uses some protocol (XMODEM springs to
mind) for this, too?

That's because the SREC upload uses the native upload code in the RCX ROM.
It works really well but has to send each byte as a pair with the bits
inverted. Also the header and trailer have to be added. The result is that
it would be impossible to type at the RCX interactively with a dumb terminal
if I used the packet scheme.

The Tcl GUI is basically a text dumper. It was able to upload the SRECs very
well under Windows, now that I have Mac/Win/Linux machines in my office, I
should be able to get the cross-platform thing working...

To make it really useful, I need to add a macro capability to translate
common words into constants, and add a little XMODEM protocol. Since the

Why the macros? To speed downloading?

The let you write code with constants, like the display formatting, without
having to do something like HEX 301F CONSTANT LCD_NUMBER and use up space
in your dictionary. It would see that LCD_NUMBER is a pre-defined constant
and substitute HEX 301F right away. Of course, the current base would have
to be considered...

Finally, it would allow stripping of comments and whitespace to make
for faster text downloads...

original XMODEM checksum is easy to do on the RCX, an advanced scripting
language should be up to the task, right?

I only ever used tcl for building a GUI (+tk) and that was some years ago, so
I'm not going to venture any opinions on how easy it is to build a
communication program with it.  Especially not if it is intended to be
crossplatform.

The new Tcl is really quite nice. I did the uploader before, I should be
able to port it to three platforms....

Just two things spring to mind:

I patched RCX_EMIT to echo \r as \r\n when RCX_ECHO is 2. Why isn't
something like this in the original code? I read something in the history of
this newsgroup about ANS-forth objecting to it, but the only thing I can
find is that ANS-forth says that end-of-line is implementation defined?

This is a great idea, Ernst. Please send me the patches and I'll integrate
it into the next release. It's not in the original code because I did not
think of it. As long as I have users that feedback useful ideas like this,
pbForth can only get better!

I once made a typo and had the whole RAM written to my screen, without
being able to abort the operation. It would be nice if pressing one of the
buttons on the RCX would do a QUIT. Maybe a cold restart is better in the
case of multiple tasks. Any ideas on how to do such a thing?

I could provide a basic image that had a task that scanned for a button. The
task switch for the interpreter happens when we send out a char, so that should
be easy to implement...

I'm playing with the idea to write an assembler for pbforth. Not that I
really need one, but it's nice to show off:-)

Yup. The H8 syntasx is pretty easy, but with assembler stuff, I'd just make
it an addition to the basic kernel and do it in source...

Cheers,

Ralph Hempel - P.Eng

--------------------------------------------------------
Check out pbFORTH for LEGO Mindstorms at:
<http://www.hempeldesigngroup.com/lego/pbFORTH>
--------------------------------------------------------
Reply to:      rhempel at bmts dot com
--------------------------------------------------------



Message has 1 Reply:
  Re: The pain of communicating with the RCX
 
(...) huh? Do you mean it just writes text to the RCX without any synchronization or checksums? Then how is it going to be an improvement over a plain ascii upload using e.g. ascii-xfr? (...) But then you can't use those constants (i.e the words, (...) (25 years ago, 10-Mar-00, to lugnet.robotics.rcx.pbforth)

Message is in Reply To:
  Re: The pain of communicating with the RCX
 
On Thu, Mar 09, 2000 at 09:04:26PM +0000, Ralph Hempel wrote: [...On a TCL program to communicate with the RCX...] (...) Uploading srec files has been without problem for me; it's uploading text that's painful. Does your program uses some protocol (...) (25 years ago, 10-Mar-00, to lugnet.robotics.rcx.pbforth)

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