Subject:
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Re: How much memory finally?
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Thu, 10 Feb 2000 18:58:59 GMT
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Viewed:
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1515 times
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Here's the latest update.
Hope we will get a clear picture of this #@$@ memory after all.
The point is that the RCX processor can address 64k of memory,
so let's divide this range into 4 equal area of 16k.
(note:16k or 16384, in hex is 0x4000).
=============== 0x0000
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| The rom area is
| first, from
| 0000 to 4000
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=============== 0x4000 = 16384
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| That's the catch: this area doesn't
| exist!!! The CPU was built with the
| idea that it might need a very large
| ROM program, so space was arrange
| for two 16k ROM chips to be add.
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=============== 0x8000 = 32768
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| This is the
| firmware area
| spaning 16k.
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=============== 0xC000 = 49152
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| this last section contains working memory space
| including 6k of free memory for your programs/datalog
| starting at 0xCEBA (=52922)
| Starting at around 0xF000 are located the
| ports for sensors and motors.
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=============== 0xFFFF
Now, the way to read the MemMap reading is to ignore the first 32k,
this value was substracted by SPIRIT.OCX. This mean that if
your first task is located at 20154 according to the memmap,
it is located in your memory map at 20154 + 32k =
20154 + 32768 =
52922 =
0xCEBA
Exactly the address given in Kekoa's note.
At last, we cracked up the secret of the memory map.
Now, why CEBA? that's because the spirit.ocx programmer
forgot to declare an empty string in his c program
earlier, I guess...
Denis.
--
Denis Cousineau, Postdoc *****************************
Cognitive psychology * *
Indiana University * Etudiant devant l'eternel *
Psychology Building * *
Bloomington, 47405 *****************************
Office: (812) 856-5217 Fax: (812) 855-1086
E-mail: decousin@indiana.edu http://Prelude.PSY.UMontreal.CA/~cousined
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Message is in Reply To:
 | | How much memory finally?
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| I'm trying to figure out how much memory the RCX has. Many sources claims that it has - 16k rom - 16k ram for the firmware - 6k reserved for our own programs Does this mean the RCX has 22k of RAM memory? What an odd number... Also, when I perform (...) (25 years ago, 9-Feb-00, to lugnet.robotics.rcx)
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