Adding extra .c files to a project

[Peter F]

I would like to split my project into a number of .c files, sharing a common .h header file. I am trying to do this under MPLAB V6.30. I put function prototypes in the header file and an #include statement for the header file in each .c file.

However when I try to compile, I get "Function used but not defined" meaning that a function called in main.c is prototyped in the header file but the definition in the other .c file is being ignored.

What am I doing wrong? Both .c files are included in the project list.

Any help greatly appreciated!

[rwyoung]

It is my understanding that the CCS compiler can't deal with more than one C file unless you use a #include "xyz.c" and force the pre-processor to pull in the C file.
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Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

[Peter F]

Thanks, I was beginning to suspect that. That's what I was doing originally to break up the files - although the extra files were saved as .h header files and brought in using #include. The problem with that, running under MPLAB, seems to be that the debugger can't resolve any breakpoints set in these files. I'll try again with them saved as .c files - maybe that will work!

I'd prefer to use the CCS IDE, but unfortunately I can't get the ICD-U40 to program the target chip - it runs the target self test fine, but always reads back FF. Works fine with ICD-2 under MPLAB...

If I could get the tools working I might be able to get on with some programming!

[Douglas Kennedy]

You may well have tried this but the ICDU needs a fair amount of power to program the target PIC. I had problems until I plugged the ICDU into an externally powered USB hub. If there is too little power you should get a message but there could be a no man's land where the USB bus doesn't see too much drain but there is not enough to get the PIC to take a download. Sharing a standard mobo USB port with the ICDU and something else could be your problem.

[Peter F]

I tried connecting the ICD-U40 via a powered hub (had to reload the usb driver), but this seemed to have no effect, unfortunately. Still read back all FF during verify.

[rwyoung]

There was a thread a while back about the ICD-U and I believe one of the problems was similar to what you are describing. The poster said that using a small ferrite torroid on the programming cable (not the USB cable) helped.

I think he was looping the programming cable through the torroid.
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Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

[pat]

I've been able to do this with no problems.

The first lines of my main "ros.c" are as follows:

[Pete Smith]

[Peter F]

I found that I could use "include" to add extra c files at compile time. However under MPLAB you can't add these files to the project (otherwise they get compiled twice!) And therefore you cannot debug them - set breakpoints etc. Maybe OK within the CCS IDE, but I can't use that due to problems with ICD-U40.

Currently working with everything in one big file, which is a pain as I keep having to use "search" to get to the code I am debugging.

[pmdebenham]

Rename the additional "C" files with a different prefix (e.g. ".c2").

Include the additional source files with #include directives as suggested by previous posters.

You can now add the additional files to the MPLAB project without it trying to compile them. MPLAB will regard the .c2 files as unclassifiable but will allow you to set breakpoints, debug etc.

I have this happily working with MPLAB 6.40 and PCM v3.182.

This still has the problem compared to really having separate "C" files that all variables and functions share the same namespace but it is the best solution you are going to get with the CCS compiler.

Regards,
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Dr Peter Debenham
Consultant
Plextek Ltd.
http://www.plextek.com

[Peter F]