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Subject: 
Re: How much memory finally? ADDENDUM
Newsgroups: 
lugnet.robotics.rcx
Date: 
Thu, 10 Feb 2000 18:28:00 GMT
Viewed: 
1333 times
  
I haven't seen anyone talk about hacking a memory expansion (hardware)
yet.

Dennis

Ralph Hempel wrote:

Denis wrote:

Well, I checked with Kekoa's memory map,
and indeed, thinks are not as simple.
And Dave was right (Why did I doubt is sacred words?)

Memory is divided into three main area of 16k.
The first is ROM, containing the base programs.
The two other sections are SRAM.

There is no user memory from 0x4000 to 0x8000 - It's all ROM space
but it might not be used.

I look at things in terms of replacement firmware, and the RCX
is very flexible in this regard.

The RAM for replacement firmware starts at 0x8000. They have some
user vars at 0xcc00, but the ROM routines let you relocate that.

You can cram all the stuff you want between 0x8000 and 0xEF00, which
gets you about 28K for user RAM total. The last 4K is memory
mapped motor drivers and the on-chip RAM for stacks etc.

I'm  still looking at how much of the area above 0xF000 is available,
but since I have not hit the ceiling yet, I'm not too worried.

Hope my 2 cents woth doesn't muddle things up too much...

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
--------------------------------------------------------

--
Dennis Williamson - Certified Y2K Complacent

Bad News: The next millenium starts on a Monday.
Good News: You get the day off.

(remove .NO and SPAM. to reply)



Message has 1 Reply:
  Re: How much memory finally? ADDENDUM
 
Hey, that's a pretty nice idea! Any volunteer? D. (...) (25 years ago, 10-Feb-00, to lugnet.robotics.rcx)

Message is in Reply To:
  RE: How much memory finally? ADDENDUM
 
(...) There is no user memory from 0x4000 to 0x8000 - It's all ROM space but it might not be used. I look at things in terms of replacement firmware, and the RCX is very flexible in this regard. The RAM for replacement firmware starts at 0x8000. (...) (25 years ago, 10-Feb-00, to lugnet.robotics.rcx)

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