Will CompactFlash work with 3v?

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I bought a CF adapter (www.pcengines.ch) but I only have 3v power
available.

Can CompactFlash cards generally work with only 3 volts or does it
depend on the card (Largan 4MB).

Thanks!
Ben

Re: Will CompactFlash work with 3v?
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Do you mean 3, or 3.3? All standard-compliant CF cards are specified to
work at 3.3 or 5V.


Re: Will CompactFlash work with 3v?
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as well as the motherboard.

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only if the host system is 3.3V compliant.  There is no guarantee to
be
so for IDE interface.

Anyway, the OP has 3V power (even for 3.3V power), which would not be
sufficient to drive 5V logics and questionable for 3.3V logic.

Re: Will CompactFlash work with 3v?
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Huh? What are you talking about? The question is, "will a CF card work
with 5V supply". The answer is, that the CompactFlash specification
requires all CF cards to be capable of operation with either 3.3V or 5V
on the power rails. I don't understand your posting.

If he has only 3.3V power, then how could his board be using 5V logic
levels?


Re: Will CompactFlash work with 3v?
On Sat, 07 Feb 2004 21:19:49 GMT, "Lewin A.R.W. Edwards"

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I think he's saying that there are motherboards that won't work with
3.3V, and having a CompactFlash working at 3.3V is irrelevant if the
IDE controller on the motherboard won't.
--
Alex Pavloff - remove BLAH to email
Software Engineer, ESA Technology

Re: Will CompactFlash work with 3v?

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AFAIK, the signalling is all TTL levels, so if the CF (powered by 3V3) is
driving signals to the motherboard then there isn't a problem there. But
the signals going from the motherboard to the CF could cause the system to
fail if the CF doesn't like voltage levels higher than 3.3V.  If the CF
had 5V tolerant inputs then AFAIK there shouldn't be a problem.  

I have never had the need to investigate whether there is anyone who makes
5V tolerant CF, so I don't know if such a device exists.

Regards,

Paul.

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Re: Will CompactFlash work with 3v?
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I apologize for causing the confusion.  I was just thinking about the
specific case for one of our client using the IDE-CF adaptor (similar
to the pcengine adaptor except for the power adaptor).  In this case,
our client was very concern about uncontrolled power loss on the CF.
So they provide a separate power line to the CF to be controlled by
the main system.  They regulated the 12V (rather than using the 5V)
system supply and shut down at about 4V.  This is to be sure of valid
logic level for the 5V system.

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Actually, if the CF is powered by 3V3, then there would be a problem
driving 5V logic on the motherboard.

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Re: Will CompactFlash work with 3v?
The CF adapter is for an embedded project (not going into a PC).
I know a CF card will work with 5v and 3.3v, but my situation is such
that the databus is 3.3v but my power supply to CF adapter is only 3v.
So all I was wondering was if the CF would work with only 3 volts power
applied to it.

The answer is YES!  That worked fine.

The only problem is, that its a 4MB card formatted with
FAT12 and the code Ive inherited is for FAT16.  I bought a USB CF Card
reader so that Windows XP/DOS could format it, but it also formats it to
FAT12.  Is there any way to force a 4MB (currently FAT12) CF to FAT16.  I now
its not as efficient, but it would make things much easier for development.

Ben


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Re: Will CompactFlash work with 3v?
snipped-for-privacy@hotmail.com (Ben Nguyen) wrote in message
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You can just copy a fat16 file template into the CF.  We have an empty
template at http://ide-cf.info-for.us/fat16.dd .  Since it was
partitioned differently from DOS, it would not be usable for DOS.
However, it works for Linux and might work for you.  We custom
partition the CF because DOS wasted 25% (one cylinder out of 4) of the
CF space.

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