Re: CF memory card vs CF wireless card

--- David Hinds <[email protected]> wrote:
> On Tue, Dec 23, 2003 at 11:06:50PM -0800, Sriram
> Neelakandan Iyer wrote:
> > 
> > I have an ARM7TDMI based chip that has an on board
> CF controller. I
> > have coded the Linux Socket Service Layer based on
> the SA11xx stuff.
> > 
> > I am able to read the CIS of a CF memory card
> properly. dump_cis
> > prints the details as per the specs I use a
> SanDisk 64MB SDCFB card
> > and i get the full CIS as per the data sheet
> properly.
> > 
> > But when i plugin a CF wireless card, the card
> detection happens,
> > but dump_cis complains "no CIS present" .. i found
> that the
> > Attribute memory was giving out randomly
> alternating values of 0x00
> > & 0xFF.
> 
> What does "randomly alternating" mean exactly?


ok.. i was wrong in the english usage ..
what i meant was that, some byte locations that are
initially 0x00 become 0xFF in the next read  ( i even
use a JTAG Emulator to read the CIS memory)
But i always see either a 0x00 or 0xff in the memory
window


> 
> > 1. Is there anything special to be done to handle
> CF
> > Wireless card (i.e. CF+ cards) to read the CIS
> space ?
> 
> All cards should behave the same in regards to
> reading the CIS; this
> is done when the cards are operating in "memory
> mode" (as opposed to
> "memory and IO mode").
> 
> > 2. Is there any init sequence to be followed for
> CF+ card power up ?
> 
> It should be the same init sequence that the pcmcia
> drivers use for
> all cards, nothing special.

I was asking about the socket drivers layer init
sequence.

> 
> The only things that jump to mind, are to verify
> that your socket
> driver is setting memory timings correctly. 

this is my question too .. Do i need to set different
memory timings for reading CIS of CF+ card.. ( note
that with the same timings i am able to read the CIS
of the SanDisk CF Memory Card ) .. so i suppose the
timings are correct.

> The pcmcia-core code
> should handle power-up sequencing (enabling the
> reset signal, applying
> power, disabling reset, and enabling output from the
> card).
> 
> How did you come to observe the difference in reset
> behavior for your
> two cards, exactly?

I doubted my reset timings (since it was driven using
a GIO on the board) thinking that the card might have
got stuck at reset state .. so i commented the reset
code and repeated the experiment .. and found that the
Sandisk memory card was still giving out proper CIS
values even without a reset. ( Dont know if this a bug
or feature on the sandisk card :)



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