Posted by Patrick Butler at 04/14/2001 9:47 AM EST
Student on team #122, NASA Knights, from NHGS and NASA Langley Research Center.
In Reply to: learning to like PBASIC + some suggestions for improvement
Posted by Joe Johnson on 04/12/2001 10:01 PM EST:
: I used to long for a more powerful language, but at
: this point so many teams are totally overwhelmed by the
: current system, I a very reluctant to give the newbies
: anything more complex to deal with.
I think the biggest problem to designing almost any programs in these chips is not so much the power of the chip but more importantly the language. There is no real sense of if-blocks in PBASIC. It makes it difficult to program using the backwards ifs with gotos. I am working on a small program that will convert if-elsif-else blocks to PBASIC backward-ifs, which could help in this. A real sense of functions would be helpful, too. We devised a scheme for emulating these by using the scratchpad as a stack, but it was never used becuase each time the function was called it had to use a different set of constants, and there was not enough space in RAM to store those constants to the RAM. Though, unless you are a hardcore coder this is not common knowledge.
Basically, the language needs 3 things, before we should jump for a new processor
1) If-elsif blocks, this could be implemented without making any real changes, run it through a preprocessor
2) Real functions, we should be able to pass arguments somehow
3) More variables, this would be the hardest to impleme nt, requiring a new processor, but not significantly new, i.e. it could function w/ the rest of the control system w/o any changes or so one would hope. I think 64 variables would be sufficient. With this #2 could be faked
.
With these three things, I think that designing the control systems would be easier and more powerful control systems could result. Of course we all know Dean Kamen would probably never allow this because it would make it too easy. After all this is about excercising our minds. And I enjoy a challenge, so I am almost biased to not wanting it myself.
Patrik