Which C compiler are and you and your customer using?  With SDCC, you  
can link to compiled assembly files rather easily.

Take a look at this page: http://www.btinternet.com/~Peter.Onion/sdcc/ 
sdcc-intro.html

Scroll down to  "Using existing assembly language modules" and there  
are nice details about getting old ASM libraries to work with SDCC.   
You can use the exact same concept to pre-compile your "protected"  
routines.  Just link to the compiled code in the command line.

I'm sure similar things are possible on other C compilers.

Matt Bauman

On Mar 9, 2007, at 1:18 PM, Mauricio Jancic wrote:

> Hi,
> 	I need to release a firmware to a customer, and he must be allowed
> to modify one of the source files (writen in C).
> 	I don't want to give him the whole code, but I would like to give
> him a (unknown format) file + the user modificable routine.
> 	Anyone can give me a pointer on how to accomplish this?
>
> Regards,
>
> Mauricio Jancic
> Janso Desarrollos
> Microchip Certified Consultant
> www.janso.com.ar
> info@janso.com.ar
> (54) 11-4502-2983
>
>
>> -----Original Message-----
>> From: piclist-bounces@mit.edu
>> [mailto:piclist-bounces@mit.edu] On Behalf Of peter green
>> Sent: Wednesday, March 07, 2007 15:55
>> To: Microcontroller discussion list - Public.
>> Subject: RE: [PIC] 16F946 AVdd / AVss
>>
>>
>>> It looks PIC16F946 has separately supplies pins for AD.
>>> If this is true, AVss should be connected directly to the
>> supply (in
>>> the same point Vss is connected). Avdd could be supplied from a
>>> separate clean  supply or from an LC filter connected
>> directly to Vdd.
>>> If the environement is clean, AVdd and Vdd could be
>> supplied together
>>> from the same power supply.
>> you could just tie them together but doing so would not be
>> the best thing from a noise perspective.
>>
>> if you want best performance the analog and digital grounds
>> in your cuircuit should be connected together at one point
>> only and there should be a filter between the analog and
>> digital power supplies.
>>
>> pic adcs are iirc only 10 bit though anyway so it may be that
>> this doesn't gain you much if you already have good
>> decoupling on the power supply
>>
>>
>> --
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>> your membership options at
>> http://mailman.mit.edu/mailman/listinfo/piclist
>>
>>
>
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