[geeks] looking for bitmap Font

Joshua D Boyd jdboyd at cs.millersville.edu
Fri Jun 28 09:15:18 CDT 2002


On Thu, Jun 27, 2002 at 05:53:00PM -0400, Dave McGuire wrote:
> On June 27, Joshua D Boyd wrote:
> > My plan is to work up a program that has an initial suggestion for
> > buttons, an initial screen support, and can do limited calculation and
> > graphing to give people an idea what I'm talking about.  Then I can
> > see who would be interested in continueing.  I don't plan to finish
> > all the math work at this point.
> 
>   That sounds like a good plan.
> 
> > I gather that designing the hardware will be pretty easy for someone
> > who knows what they are doing.  The part that I'm not really familiar
> 
>   Umm, well, not really...this would be a nontrivial development effort
> from the hardware side.  Big displays and fast processors are
> nontrivial to design with.  I'm pretty sure I can do it, though.

How big and fast are we talking about?  I was thinking a 160x120 B&W
display, and I think those seldom use more than a 40pin connecter
cable (although perhaps that is just the less cheap hobbiest package).

And I forget what chip you mentioned.
 
> > with will be what it will take to get a basic scheme running on the
> > calculator well enough to move the code from the software prototype
> > over.  I think it might be best to write a memory manager in scheme,
> > and it would be nice to have an on calculator debugger I think.  Also,
> > I want to make sure it is actually a good scheme.  For instance, it
> > should allow deep recursion without fear of a stack over flow like
> > good unix schemes will.
> 
>   Is there a decent scheme available for any fast embeddable processor
> (Dragonball maybe?) that you're aware of?  If not, we could
> theoretically do something like that DragonIX thing that I sent the
> URL about, and very tightly tailor the OS to running just the scheme
> environment.

Well, a number of the smaller schemes would be suitable for running on
barehardware.  But I'm not aware of any specifically tailored for any
specific chip.

The DragonIX would be a workable starting place.  That certainly would
allow us to blow the doors of any competition for processing speed.  I
believe the 89s and 92 are running a similar motorola CPU at speeds
like 16mhz (I don't know if the have a seperate FPU).  One concern I
have is the lack of an FPU.  The FPGA on the DragonIX isn't going to
do us much good since it is too small for a decent FPU to my
understanding (a few hundred logic gates when we need a few
thousand).  It certainly has a lot of ram.  

I don't know what the cost of the indivual parts are, but the dev kits
are 600 euro (which is pretty close to what the cost would be in dollars).
 
> > What are you looking for exactly in the way of logical operations
> > anyway?  Just or and xor not as functions to call in the calculator?
> 
>   Yup, just that sort of thing.  Maybe some hex arithmetic too, for
> address calculations.

Hex arithmetic and base conversion and boolean can all be added.

-- 
Joshua D. Boyd



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