Subject:
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RE: 8450 Mission / Cybermaster expansion
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 5 Nov 1999 16:46:12 GMT
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Original-From:
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Laurentino Martins <LMARTINS@MARKTEST.PTihatespam>
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Viewed:
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628 times
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At 16:07 05-11-1999 Friday , Ralph Hempel wrote:
> > > Yes, but so is the ROM in the RCX. The trick was to figure out the upload
> > > sequence (via the serial link) and then Kekoa figured out the format
> > > of the packet.
> > >
> > > I'll have to look at the Cybermaster serial code in NQC, but if there
> > > is an ability to place arbitrary bytes in memory, and run code from
> > > an arbitrary address (or fixed somewhere in the limited RAM) then it
> > > is possible to make an umbilical FORTH that does NOT use the standard
> > > opcodes...
> >
> > No, the OPCODES are interpreted by the firmware, not the ROM code.
>
> OK, i guess we need to get terminology straight. The ROM is the masked code
> in the RCX/Scout/Cybermaster.
The ROM is a list of Hitachi assembler routines that interact directly with the hardware and do some of the dirty work needed for the firmware to load and work.
> It was "looked at" because I'm pretty sure
> Kekoa wrote a little dump routine and loaded it into the RCX like
> replacement firmware - in other words, he used the protocol that
> loads the firmware into the RAM to load a dumper so that the ROM
> could be reverse disassembled.
??? *scratch* *scratch* :-\
This is news to me.
I have to see if I can find those posts...
> The firmware on the CD is loaded into the RCX using the same protocol, but
> since it was in a nice Srecord format, disassembling it probably wasn't
> too hard. Commenting it - that's a different story altogether.
> Now, given that the opcodes are similar between the Cybermaster and the
> RCX, I wonder if a little "dumper" could be loaded into the Cybermaster...
Let's get this straight:
. When you press the power button on the *CyberMaster*, the firmware is already in memory and running (!).
. To communicate with the CyberMaster, the PC needs to exchange some info with the *firmware* so they can talk.
At least in the *CyberMaster* you can not talk with underling ROM and you can not read it's code.
You also can not read the firmware code, and the *only* thing you are allowed to do is to send opcodes to the firmware and expect it to follow your orders.
Since there is not Opcode similar to the PEEK( address ) or POKE( address, value ), that is to read or write to memory, you can not do anything the firmware does not allow you to do.
You can nevertheless read the contents of the variables, sensors (and others) of the firmware, but *only* because there are specific Opcodes for it.
I sincerely hope to be proved wrong! :-)
Laurentino Martins
[ mailto:lau@mail.telepac.pt ]
[ http://www.terravista.pt/Enseada/2808/ ]
Neither technology nor efficiency can acquire more time for you,
because time is not a thing you have lost. It is not a thing you ever had.
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