From: email@example.com (Anthony J. Albert)
Subject: Re: PCMCIA -> CF -> ATA Adapter (A question on addressing in CompactFlash and PCMCIA)
Date: Tue, 31 Dec 2002 22:07:17 GMT
Organization: University of Maine System/MSLN
NNTP-Posting-Date: 31 Dec 2002 21:57:16 GMT
X-Newsreader: Forte Free Agent 1.21/32.243
On 30 Dec 2002 07:17:00 GMT, firstname.lastname@example.org (Eric) wrote:
>I'm trying to convert a SanDisk PCMCIA/CF card to work for the ATA interface on
>the CF side. Basically, I want to make an internal HD into an external HD for
>my laptop. I couldn't find a PCMCIA/IDE card and I knew the CF specifications
>were VERY similar.
>I am NOT trying to connect a PCMCIA card to the IDE connector of my desktop.
>I am trying to connect an IDE drive to the CF connector on my PCMCIA card on my
>Basically, I want to have an ATA drive act as a compact flash card on my
>With that said, I used the following link as a reference along with some other
>sites to help me identify the appropriate pins on each device.
>Is it possible to just connect the CF signals to the IDE signals mentioned in
>this document and have it work? The CF spec has 8 additional addressing lines.
>How are those used in the CF specification? How are they used in the PCMCIA
>If I tied them low, would my laptop still recognize the hard drive? Should I be
>tying it low? Should I leave them open? High? Or does it depend where the
>PCMCIA slot is mapped for my computer? If the CF card doesn't require it, then
>what are they normally used for? My guess is they're not essential to the CF
>since they can be disregarded on the CF adapter shown in the link above but are
>they essential to the PCMCIA interface? Why does the CF spec even have it? For
>future use maybe, so that one day higher capacities can be achieved???
>I'm not sure if I'm being clear in my request or explanation, so please be
>patient with me. Hopefully, I'm being clear enough that you can understand me
>and be able to help.
There are adaptors around that do this, letting you plug an IDE drive
into a PCMCIA card-slot.
(Google search: "PCMCIA to IDE", including the double-quotes.
However, I haven't ever seen one that was under your price point of
US$20... most of them have been more around US$50 - $100.
That said, I think that the WWW page which you noted in your posting,
above, makes things pretty clear. It appears that there are a number
of pins which PCMCIA supports which IDE does not - the address pins
you mentioned. I'd imagine that, since they are output pins, you
don't need to do anything with them. There's a number of IDE pins
which are marked as "GND" which should be grounded, and then there are
the IDE signals DMAREQ, SPSYNC, DMACK, which I take to be "DMA
request", "Spindle Sync", and "DMA Acknowlege", respectively. It
appears that the PCMCIA interface doesn't really have a way to use
these pins. It is possible that one might contrive to hook them to
the unused PCMCIA address lines, but that would appear to me to be
Doing a tally of the IDE lines listed in that WWW page, all 40 are
accounted for, so mechanically, it looks like a pretty straightfoward
connection - just wire them straight through, as the signals all seem
to be the same type... PCMCIA and CF were designed with the IDE
interface in mind as a model, after all.
Software is going to be the tricky part. You may need to write a
driver for this - I have my doubts that the OS inside your laptop will
be able to talk to the IDE drive without a driver. Perhaps a starting
point would be the PCMCIA-cs drivers for Linux. See:
Really, though, it looks like it's not going to be too terribly hard
to do this project, judging from the looks of the commercially
available equipment to do the job.
I'd have to say that thinking about CF here is getting you off track:
what you're really doing is connecting an IDE drive to a PCMCIA port.
If you happen to use a PCMCIA/CF adaptor as a hardware shell to make
building the connectors easier, well, so be it... you'll only need to
be concerned with finding which pins of the PCMCIA side come out where
on the CF side... so that you can wire them to the IDE side. I'm
thinking that perhaps you should disassemble the PCMCIA/CF adaptor,
and remove the CF socket - that should allow you to solder the
conductors of a standard IDE ribbon cable in its place, which could
then be run to the drive.
Hope this helps,
Anthony J. Albert