How to include a Microchip ASM file(s)?

[s_mack]

Hey there. On this page: http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en020434

There is a document and a zip file relating to the implementation of a PID controller using a pic 18.

I'd like to give this a try to see if it produces a better result than our home grown solution. But there's really no documentation on usage beyond the rather abstract.

I don't know how to include such a file(s).
I don't know if I need to include both, or if the math one is implied somehow.
Both files seem to include p18f452.inc (where's it getting that from?) - does it matter that I'm not using a pic18f452 chip? I'm using a pic 18f4480.
I don't really know how to call the various functions, etc or to use it at all as virtually no syntax is given anywhere... but I'll cross that bridge when I get there.


Is there a way to convert this ASM file to a more readable c file? Probably not if my googling results were any indication.
Thanks.

[s_mack]

bloody hell this has been a frustrating and wasteful day.

So I gather I can't do the above.

I can't convert ASM to c.
I can't include an ASM file and access its functions from my c program.
The vast majority of Microchip's "Application Notes" files are completely useless to people programming in c?

this can't be the case.

[FvM]

As you already found out, the Microchip PID asm sources can't be simply included in CCS C for two reasons:
- they don't provide a C interface, it has to be created also when using the sources with C18
- Microchip assembler isn't fully compatible with CCS assembler

I assume, that it's generally possible to reuse the sources in a CCS project, but this involve a lot of work and requires a deeper knowledge of CCS C low level coding details. It's most likely more easy to extract the algorithm from the source and rewrite it in C. When debugging an assembly project, you have to understand the code's operation anyway, which is already half the way to rewrite it.

On the other hand, the basic PID agorithm is pretty straightforward, I can't see, if the AN937 code has any features, that pay the implementation effort.

[s_mack]

The biggest reason I'm looking at it is that it seems (though I can't read assembly code) that they do the entire process without the use of floats. Our existing PID controller routine is almost entirely floats. And I'm having a ROM issue

Plus we have integrator windup issues that I've never been able to resolve so when I saw their document it was a "why reinvent the wheel" moment.


Anyway, I wonder... can I use an Assembler to generate .o files, then include them in my project and reference them like normal? Would ccs choke on that or ?

Hmm.

Or maybe I should just switch to C18. According to microchip, you can freely mix c and ASM files to your heart's content with it. So I don't mean this in any bad way... but why am I using CCS anyway? I mean that seriously. I was just handed the software and shown how to program our boards and make minor adjustments so I don't know where or why ccs came into it at all - it was just installed for me. Are there particular benefits to it? Will our code simply not work if I used C18 instead? I don't want to cause myself more headaches or spend $500 for no reason.

[bkamen]

Ooo, C18, I wouldn't go there.

First, C18 vs. PIC-C won't fix your float problem. The PIC family of MPU's are all without FPU's. So C18 would have to generate messy code to handle floats just like PIC-C would have to for any other integer only MPU.

AND, in my comparison for C18:

More $$
More ROM (code isn't typically as efficient as the compiler has GCC roots)
Less built-in PIC friendly functions
More Overall Hassle to use.

It was not pretty.

Anyway - you can mix ASM into PIC-C as well. I've done it in the past when I need to super-tweak a routine or just prove out something else when working with CCS to integrate new chips that have new functions.

CCS also has a pretty reasonable maintenance program.

Regards,

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[s_mack]

Ok.... so then... how??

I've asked here and on Microchip's forum and on stackoverflow and nobody's really given me a way to do it. Seriously, I've spent probably 12 hours just trying to figure out how to include these asm files and access the functions in them.

I've now downloaded the evaluation version of C18 and at least right away it SHOWS me all the files (ASM and c, not just one or the other).

I'd rather stay with CCS rather than running into other problems. For example, I loaded up my project without the ASM files in C18 and hit "build all" and I have errors where it compiled without so much as a warning on CCS. So obviously switching is going to introduce headaches as well.

The question is: will I be able to faster integrate my c into C18 or find a way to integrate these ASM files into CCS?


A couple of times I've gotten the response that I should just write the PID code in c. Programmers typically have the attitude of "don't reinvent the wheel"... there's a library sitting in front of me already written and I want to take advantage of it.

It shouldn't be this hard.

[bkamen]

Ok, I'm looking at the link with the ASM files. I am curious though as to how you see 'C' files in C18 when the link you provided above points to a PDF and ZIP (containing only .ASM's)

Can you post the 'C' file up here so we can see it...


Otherwise you can do this a couple of ways..

1: break down the asm into functions that contain the desired code
2: write functions that essentially jump to the ASM routine you want.

I've done the former but not the latter. The latter would be easier for you.

the PIC-C help file lists the former method as:

[bkamen]

And don't forget that floats are ugly with EITHER compiler because of the fact an integer MPU is being used.

(I just wanted to mention that again as I read the thread again)

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[s_mack]

No, that link only has ASM files. I mean with c18 I can open my project that contains my c files but also have the ASM files and include them just like I'd include another c file using ccs. In other words it seems to be perfectly happy mixing and matching the two languages in a project. The compile errors I'm currently getting are all related to my h files.

Anyway, I'd prefer to stick with ccs because I've been working with it for awhile.

I just found the #ASM listing in the help file and I'll play with doing it that way.

Seriously though, it shouldn't be like this. CCS should just be able to include an ASM file (ESPECIALLY if it has an #ASM directive!!) and I should be able to call the functions as though they were sitting in an included c file. It should just automatically recognize that its assembly and do its thing. Its not like we're talking French and Spanish here.

[s_mack]

[bkamen]

[s_mack]

Thanks. I didn't know there was a CCS linker. I'll check that out.

No, I didn't ask them by email.

Thanks for your help. It vaguely seems like it might be coming together

[bkamen]

[bkamen]

[s_mack]