Adding RAM to RC
 

Posted by Chris Orimoto at 2/16/2001 9:01 PM EST


Student on team #368, Kika Mana, from McKinley High School and Nasa Ames/Hawaiian Electric/Weinberg Foundation.



Hey, it is legal/possible to add RAM to the Robot
Controller for the purpose of adding variables to
the Pbasic program? If so, then does anyone
know how to do this?

Your help is much appreciated...

Chris, #368

Only Scratchpad RAM
 

Posted by Joe Johnson at 2/16/2001 9:58 PM EST


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.


In Reply to: Adding RAM to RC
Posted by Chris Orimoto on 2/16/2001 9:01 PM EST:



No legal way to add RAM.

But... the scratchpad more than doubles your RAM. You
have to access it via PUT and GET, but other than that
it is pretty useful stuff.

If that isn't enough, you MAY consider doing some crazy
stuff like using EEPROM memory. This won't work well
if you are writing stuff to memory EVERY loop, but once
in a while (once per second or per several seconds) you
can probably get away with. Using this, you have two
enemies. First, you have the relentless tick of time.
If you don't answer the bell often enough
(specifically, if you miss 6 data packets -- 150msec)
the master CPU will call the fight, so to speak.
Second, the EEPROM's only have a finite life. If you
write to them too often (millions typically) they get
stupid.

The final and perhaps best suggestion I have it to reuse
variables within one loop. It can be tricky, but you
can save a lot of RAM space. For instance, do all your
arm stuff early in the loop, then you are free to use
the variable later in the loop for other stuff.

I hope this helped.

Good Luck,

Joe J.