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RE: PCMCIA Standard CIS access
- To: "'Lewin A.R.W. Edwards'" <larwe at larwe dot com>,"'eCos discussion'" <ecos-discuss at sources dot redhat dot com>
- Subject: RE: [ECOS] PCMCIA Standard CIS access
- From: "Trenton D. Adams" <tadams at extremeeng dot com>
- Date: Wed, 27 Jun 2001 17:50:49 -0600
- Organization: Extreme Engineering
I'm a complete and TOTAL moron!!!! What do you know, I didn't have the
card fully in the slot. Anyhow, I'm still having troubles, but I'll try
and figure it out my self first.
> -----Original Message-----
> From: Lewin A.R.W. Edwards [mailto:larwe@larwe.com]
> Sent: Wednesday, June 27, 2001 4:53 PM
> To: Trenton D. Adams; 'eCos discussion'
> Subject: Re: [ECOS] PCMCIA Standard CIS access
>
>
>
> > From what I understand, the card does not have to
> have power enabled
> >in order for me to read it's CIS. Correct? If so,
> does anyone know
> >what MIGHT be the problem with reading the CIS? I
> keep getting a READ
> >FAIL interrupt when attempting to read the Card
> Information Structure.
> >Is there maybe a standard reason in most PCMCIA
> controllers why this
> >might happen? I doubt it! LOL
>
> You need to refer to the PCMCIA spec here. Don't
> quote me on this, and
> above all don't implement anything based solely on my
> say-so, but IIRC the
> powerup process goes something like this:
>
> * socket power cut off
> * when both card detect pins go active (indicating
> card fully inserted),
> wait for some period of time (defined in the spec)
> and check the LVD1/LVD2
> pin state to see what the card expects for Vcc.
> * apply Vcc to the card and wait some period of time
> (defined in the spec)
> for the card to power up.
> * read CIS.
> * even if your card is an old flash device requiring
> Vpp=12V, you should be
> able to use it in read-only mode with no Vpp applied.
>
> Most PCICs with integrated power switching will
> automatically cut socket
> power and tristate all outputs going to the socket
> when either card detect
> pin floats (indicating card at least partially ejected).
>
> You most definitely do need to power the card in
> order to read its CIS. And
> it most definitely IS possible to damage cards by
> setting up the wrong
> supply voltages. It is also conceivable that you
> could damage PCMCIA cards
> by applying signals when the card isn't powered.
>
> BTW, if the card is a CF card, it will always be safe
> (and always possible
> to read the CIS) by powering it up at 3.3V. CF cards
> by design must operate
> at both VCC voltages.
>
> This is why I suggested Linux, since it will take
> care of all the PCMCIA
> details for you, and you wouldn't even need to write
> drivers for many
> common cards...
>
>
> -- Lewin A.R.W. Edwards
> Embedded Engineer, Digi-Frame Inc.
> Work: http://www.digi-frame.com/
> Tel (914) 937-4090 9am-6:30pm M-F ET
> Personal: http://www.larwe.com/ http://www.zws.com/
>
> "Far better it is to dare mighty things, to win
> glorious triumphs, even
> though checkered by failure, than to rank with those
> poor spirits who
> neither enjoy much nor suffer much, because they live
> in the gray twilight
> that knows not victory nor defeat."
> (Theodore Roosevelt)
>
>