> Good luck with your project.  Personally I have no need for Compact Flash
> cards at all.  If they happen to be compatible with my hard drive
> interface,
> that'd be a bonus, but doesn't really matter.
>
> I just finished soldering some parts into the board, I guess I'll use
> wire-wrap wire to connect everything point-to-point underneath the
> protoboard ... it usually seems to work.
>
> I just have 2 small questions if anyone feels like answering.
>
> 1. Am I gonna need extra memory besides the PIC16F877's memory?

        Almost certainly yes. If you aren't going to modify sectors on the drive
that already contain data then you could theoretically get by without
additional memory.

        The issue is that a hard drive does things based on sectors, you can't
write just one byte, you MUST write an entire sector (512 bytes). Therefore
everything you do with the drive is on a sector basis. I'd certainly
recommend either getting additional memory as a sector buffer (I use an
EEPROM) or use a different PIC. The 18F452 has the amount of memory you
need.


> Oh, also, isn't there a memory card (sandisk or something) that has a SPI
> interface?  Why would anyone bother with Compact Flash if that's the case?
> Wouldn't it be WAY easier to just use the PICs SPI port than to setup the
> IDE interface?

        SD cards have an SPI interface. Again, transactions only happen on a sector
by sector basis, therefore you can't just write a certain byte, you must
write a whole sector.

        As to why one would go CF? Well, in my case my project started out as a
hard drive interface, going CF was an option I always wanted to leave open.
On top of that CF was far cheaper then SD at the time.

        These days I'd certainly go SD, in fact a project I have in mind for the
future will do basically the same thing as my car more, but be small enough
to fit in a pocket (guess what name it'll have... :) TTYL


----------------------------------
Herbert's PIC Stuff:
http://repatch.dyndns.org:8383/pic_stuff/

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