> It does if it's a high volume project and a cheaper processor could  
> have been used.

I dunno.  Judging by high volume consumer gear, the price of chips  
doesn't have a lot to do with the product price.  If you have THAT  
high a volume, apparently you start negotiating with manufacturers for  
lower prices on the chips.  Thus a high-volume consumer digital camera  
costs less than a microcontroller "evaluation board" even though the  
former has chips that dwarf the complexity of the latter, and wouldn't  
even be purchasable in low volumes...

In this case (FAT filesystem on a flash card) using a high level  
language has an advantage I haven't seen explicitly stated yet.  Since  
most of the "complexity" of the problem is external to the PIC itself,  
the advantages of dealing directly in assembler are lessened AND the  
PORTABILITY of the code is VERY MUCH IMPROVED by being in C.  (In many  
cases, portability is not important, because the application is so  
inherently chip-specific anyway.  But this isn't one of them.)  You  
could write some carefully portable C code (an art in itself, alas)  
that would work on your initial selection of a 16F628 chip, and be  
nearly-instantly installed on an 18F chip when you discover you need a  
lot more program space, or on a 24F chip when you discover you need  
more speed, or on a freescale chip if Microchip pisses you off and you  
decide to switch vendors (although usually it seems to go the other  
direction :-)

That said, a FAT file system isn't THAT complex, and an implementation  
written in assembler should be pretty doable by someone with  
experience.  And I would think that there would be a lot of people  
interested in seeing the resulting code, especially if it turns out to  
be significantly smaller than the C versions floating around.  (In my  
experience, FAT implementations tend to get pretty bloated.)

BillW

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