RE: [ECOS] PCMCIA Standard CIS access

["Trenton D. Adams" <tadams at extremeeng dot com>]

My particular controller requires that I set an "Enable" bit in order to
make a card access.  I'm assuming this includes a Attr/CIS type of card
access.  Anyhow, it doesn't seem to matter what I do, whenever I enable
this bit, it locks the program until I eject the card.

Also, when you say LVD2 and LVD1, I assume you mean the two pins that
are for voltage selection, correct?  If so, mine are VS1 and VS2.  VS2
is set which must mean 5V since that's what the card is.  VS1 is also
set, but I don't know what it represents since the documentation says it
differentiates between 3.3V and X.X-V cards.  But what does the X.X
mean?  How can I possibly know what an X.XV is without a number?

	> -----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)
	> 
	>