RE: [ECOS] PCMCIA Standard CIS access

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

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)
	> 
	>