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RE: CF custom implementation

To: "'Kiran Thota'" <Kiran_Thota@pmc-sierra.com>, "'Ulrich Eckhardt'" <eckhardt@satorlaser.com>, <linux-mips@linux-mips.org>
Subject: RE: CF custom implementation
From: "Bogdan Vacaliuc" <bvacaliuc@ngit.com>
Date: Sat, 7 May 2005 09:51:30 -0400
Importance: Normal
In-reply-to: <9DFF23E1E33391449FDC324526D1F259024380CB@sjc1exm02.pmc_nt.nt.pmc-sierra.bc.ca>
Organization: NGI Technology, LLC
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
On Friday, May 06, 2005 1:33 PM, Kiran Thota wrote:

> Another question: If I rework the board so that the wires coming to
> MEMR and MEMW are rewired to IOR and IOW respectively, does it work
> in TrueIDE mode? Just a thought!  

No.  TrueIDE mode changes the meaning of many input/output pins, and thus is 
significantly different from PCcard IO mode so that
this will not work.

Also, you should bear in mind that (P)IO mode is more similar to IDE mode than 
it is to memory mode.

To operate the CF/CF+ card in memory mapped mode you will need the following 
signals:

A[0:10]
D[0:15]
-CD1, -CD2
-CE1, -CE2
-OE
RDY_BUSY
-REG
RESET
-WE
WP

Refer to the "CF+ & CF SPECIFICATION REV. 3.0", pg. 24-30 for details.
http://www.compactflash.org/cfspc3_0.pdf

If your cards are not going to be removable, you can get away with tying up/dn 
some lines.

Also, please note that on pg. 89, the specification allows for alternate ways 
that a CF card may 'enter' either trueIDE or memory/io
mode.  Please be aware of this, because certain software implementations may 
inadvertently cause -OE to stay asserted for an
extended period of time, thus causing the card to spontaneously switch modes.  
This results in the card seemingly becoming opaque
until the next reset or power cycle.


Best Regards,

-bogdan


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