Dev for OSTC

[codeisart]

Hi,

Few questions about developing for the OSTC / hwOS. Great looking computer btw and thanks for making it open source, you guys rock!

Managed to get everything build with a bit of patience. The Fonts/Icons .inc paths seemed to prove the hardest problem. You might want to update the docs on that.

* Were you so limited on memory that the code needed to be in assembler? I'm new to embedded development, so this seems excessive to me. C isn't that much bigger. I assume this wasn't just a style thing?

* Is there any emulation available to test on? Obviously MPLab has as simulator, but without the screen and sensors, it seems a bit pointless, unless running the test suites.

* Is there any development hardware available? Or different rates for developers? I'm keen to try out some ideas and while I would like a model myself, I would like one exclusively for dev also.

* Is the Sport identical hardware OSTC3? I was wondering if the difference was simply the software installed on it. This is just from looking at the photos, so excuse my ignorance on this.

Anyway, keep up the good work.
Cheers,
James.

[heinrichsweikamp]

codeisart Wrote:
-------------------------------------------------------
> * Were you so limited on memory that the code
> needed to be in assembler? I'm new to embedded
> development, so this seems excessive to me. C

It's a mix of C and ASM. Why, good question... But no, we won't recode anything in C, sorry.

> * Is there any emulation available to test on?
> Obviously MPLab has as simulator, but without the
> screen and sensors, it seems a bit pointless,
> unless running the test suites.

No, we're debugging on dedicated hardware using the processors on-chip debugging interface here.

> * Is there any development hardware available? Or
> different rates for developers? I'm keen to try
> out some ideas and while I would like a model
> myself, I would like one exclusively for dev
> also.

Yes, we have dev-only devices (Not suitable for diving due to different reasons). If this is something you need, contact us directly: info@heinrichsweikamp.com

> * Is the Sport identical hardware OSTC3?

No, is similar but the OSTC3 has the external optical interface, for example.

You can run OSTC Sport firmware on OSTC3 but not OSTC3 on OSTC Sport.

Regards,
Matthias

[Stefan]

Hi Matthias,

I found a hint on the page of microchip, that the C18 compiler is no longer available.

Is there a replacement for it or is it possible to use the Standard-Eval Version? (If I get it right the difference is that the optimization and the extended instruction set is not available after the 60 day testing period).

Regards,
Stefan

[jak]

Stefan,

I got some issues with the eval version. It works fine but just sometimes the generated code doesn't fit into the memory so those optimizations are really useful.


R, Janos

[Stefan]

Hallo Janos,

thanks for the information. At what degree do you think the optimizations are necessary?

I was told (in the microchip forum) that the replacement for the C18 Compiler is the XC8 compiler. With optimizations that one is available in a free version without optimization and two editions: standard (with 20-25% optimization) and pro (50% and more optimization).

Regards,
Stefan

[jak]

Hi Stefan,

All I know is that my compiled code didn't fit into the program area at some point (I was adding quite some extra code back that time). Matthias' compiler did the job so I switched the compiler to get those optimizations available and the same success compilation.
Matthias also did some optimizations and freed up some space but I don't know if the C18 w/o the optimizer would do the job now as I already have optimizations enabled.
...did you try to compile the code with the eval version of C18? Or you just worried about using a non-optimized code in real life situation?

I had some issues with the XC8 and I didn't like it so I switched back to C18 (non-eval version).

> At what degree do you think the optimizations are necessary?
There are two levels:
1. The compiled code won't fit into the program memory:
This won't be a problem while you dive as you won't even be able to load it on your computer. You will have to remove some other part(s) of the code to be able to successfully compile the code. E.g. before I switched to the non-eval C18 I used to have my code without the extra languages - DE, FR, IT - included. With only EN added my compiled code fit into the program area w/o optimization.

2. The compiled code will fit into the program memory although it will have some extra cycles so won't be as speedy as the optimized:
As I know there are plenty of free cycles available, not sure if this would be a real life problem for OSTC. Could be only a hypochondria, but I found the code more speedy with optimization - although I also optimized the code a lot to make the screen updates more speedy.

Try to use the eval for development. If you want to take your code under water make sure you have a secondary computer with you. If you want to make it the primary - or the only one - spend enough time testing it and try to get a non-eval for the final compile.

R, Janos