Subject:
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Re: How do I delete firmware from firmware?
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Thu, 18 May 2000 16:55:04 GMT
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Viewed:
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3776 times
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Ralph Hempel <rhempel@bmts.com> wrote:
> > I asked this question under a confusing subject that
> > people may have missed so I am asking again. How does
> > one delete firmware from firmware. I am looking for a
> > solution for pbforth but the question could have be asked
> > for LegOS or Quite C as well. If I get no answer I will
> > try gross things like zeroing the first 50 bytes of code,
> > turn off sll interrupts and then jumping to the h8-300 reset
> > vector. Some variation of this will probably work but I
> > wondered if there was an "official" way to do this. I notice
> > from the unofficial internals doc that there is an opcode
> > for this but no rom entry is listed for this function. Has
> > anyone looked at the rom to see what it does?
>
> I think if you do a direct jump to 0x03ae, it will init memory
> and essentially start the brick from scratch. At least that's
> what I read from the internals doc...
This sounds correct. In C, this is how I do it:
/* Delete the firmware */
*(char *)0xffcc = 1;
(*(void (**)(void))0)();
Indeed, *(void (**)(void))0) is the reset vector, whose value is 0x03ae.
0xffcc is timer 0. I forget what effect setting it to 1 has, but I seem to
remember that setting it to 1 gave nicer results than not doing that. The
Lego firmware that came with the original RIS did this (but I don't know
about later firmware versions).
-Kekoa
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Message is in Reply To:
 | | RE: How do I delete firmware from firmware?
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| (...) I think if you do a direct jump to 0x03ae, it will init memory and essentially start the brick from scratch. At least that's what I read from the internals doc... Cheers, Ralph Hempel - P.Eng ---...--- Check out pbFORTH for LEGO Mindstorms at: (...) (26 years ago, 18-May-00, to lugnet.robotics.rcx)
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