Re: [linuxsh-dev] !!! QUESTION !!! --- What the difference between Memory mode and I/O mode in compact flash?

[Stuart M. <stu...@st...>]

PCMCIA actually supports three different address spaces:
 - attribute	- read by the CPU to determine what card is plugged in,
                  and possibly to configure the card as a whole.
 - I/O		- used for control registers of device(s) on the card,
                  eg for a serial port pr network device
 - memory	- normally used for real memory: RAM, Flash etc, but can
                  also be used for device control registers.

They share the same address and data lines, but different control lines go
active to indicate which space is being read or written.

All cards must support config space, whether they support memory or
I/O depends on the card designer.

When a card is plugged in, it is always assumed to be a memory only card.
This allows the Card Information Structure (CIS) to be read from the card,
which tells the driver what types of card this is. If it is an I/O card,
or multifunction card (I/O and memory), then the PCMCIA interface hardware
must be told this, and certain pins on the PCMCIA interface change their
function to support I/O addressing.

I suspect this is what you mean by memory mode and I/O mode.

Stuart


On Fri, 12 Apr 2002 18:12:25 +0200
fg...@ti... wrote:

> If you know explane to me.
> 
> Thanks.
> 
> _______________________________________________
> linuxsh-dev mailing list
> lin...@li...
> https://lists.sourceforge.net/lists/listinfo/linuxsh-dev


-- 
Stuart Menefy                                        stu...@st...
STMicroelectronics Ltd                         ST Intranet: mo.bri.st.com
Bristol, UK                         Rest of the World: www.linuxsh.st.com