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Subject: 
RCX Boot
Newsgroups: 
lugnet.robotics
Date: 
Tue, 17 Jun 2003 11:25:25 GMT
Original-From: 
Fauze Valerio Polpeta <fauze@lisha.ufsc.ANTISPAMbr>
Viewed: 
785 times
  
Hi,

I'm a research of the Laboratory for SW and HW Integration of the Federal
University of Santa Catarina in Brazil and I'm involved in a project that
consists in adapt our operational system (EPOS - Embedded Parallel
Operating System) to the RCX plataform.

Basically what we do is concatenate five binarie files (applications) and
send them to the RCX. So when the bootstrap is loaded at the 0x8000 the
system begins your work arranging itself in memory.

However I'm in trouble with the RCX unlock. I thought that the key string
"Do you byte, when I knock?" was just a string searched by a state
machine of the RCX firmware download protocol. Is it?! I'm starting to
think not
because compiling a program with the gcc, removing the its elf header
and uploading this code to the RCX I've got unlock error. Must be the
key string at the end of the file?

Basically I'm asking if is possible compile program remove the header, so
we've got instructions at the first byte, and put it in the RCX. Why
that?
I will make that just with the first of the five binarie files, because
it is the bootstrap, after we jump to the second (setup) over its elf header
and start loading itself and each others with a libelf.

Is that possible? I have no success 'til now because of the unlock
problems! All the programs that I saw, the key string is the first thing
declared and, all the program is single binarie file!

Just checking the data that is uploaded to the RCX I compiled the code to
srec format an changing the softwares that make upload I saved in a file
the exactly data that is uploaded to the RCX (the srec haders are
interpreted and removed on PC), after that I can say to you: At the
beginnig the content is the same of a elf file with its header
removed...really the same, the unique difference is that the elf file has
the key string in the middle followed by some elf data and the srec has
the string at the end. So, make no sense this doesn´t work!!!

I hope you can help me or indicate someone for that!


Fauze



Message has 2 Replies:
  Re: RCX Boot
 
"Fauze Valerio Polpeta" <lego-robotics@crynwr.com> wrote in message news:Pine.LNX.4.44.0...ufsc.br... (...) string (...) to (...) elf header (...) the (...) A quirk in the RCX ROM loader is that it only checks address range 0x8000 - 0xCC00 for the (...) (21 years ago, 17-Jun-03, to lugnet.robotics)
  Re: RCX Boot
 
(...) When you say it doesn't work, what happens? Do you hear the long low buzz sound that Dick Swan mentions? Or, does the RCX just crash? I'm not very familiar with ELF files, but I did look up the format. Are you certain your program is all code? (...) (21 years ago, 17-Jun-03, to lugnet.robotics)

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