64-bit Data Flash Access Problem [MPC8245]

[Steven Blakeslee]

It sounded like the problem you were describing is caused by software
floating points.  If the bus size is 64bit then you must write 64bit.
Software floating points cheat this by doing two consecutive 32bit writes,
the 8245 will not allow this.

-----Original Message-----
From: Augustine Nebu Philips [mailto:nebuphilips at eudoramail.com]
Sent: Wednesday, September 24, 2003 1:35 PM
To: linuxppc-embedded at lists.linuxppc.org
Subject: RE: 64-bit Data Flash Access Problem [MPC8245]



Steve,
 I tried to use fp assembly instructions (like lfd). But my assembler has
problems and doesnt let me generate my binary. I'm sorry I couldnt properly
get you... Should I make use of sw floating points..? That means, should I
access 64-bit data only through 64-bit operations..?

Thanks and Regards
Nebu
--------- Original Message ---------

DATE: Wed, 24 Sep 2003 13:31:50
From: Steven Blakeslee <BlakesleeS at embeddedplanet.com>

>Are you sure you are not using software floating points?
>

>Subject: 64-bit Data Flash Access Problem [MPC8245]
>
>
>
>Hi
>I have a set of 8 1GB data flash chips (Samsung) on an MPC8245 Ref. Board.
>These are on a 64-bit bus-mode.
>
>-------DBUS_SIZ[0-1]:DBUS_SIZ[2] = 110b -------
>
>All 8 chips are selected by a single chip select (RCS1). Trying a 32-bit
>read from the Data Address Location after giving the Command to Access the
>flash IDs, only 4 flashes on a common byte lane seem to be responding.
>32-bit writes appear only on the DH[0-31] and not on DL[0-31].
>
>I am not very clear as to:
>
>(a) How do we perform writes to send out data out on
>    all 64-bits of the bus..?
>(b) How would we ideally access 64-bit data through 32-    bit reads..?
>(c) Or must we *have* 64- bit read/write
>    instructions..?
>
>many thanks in advance for any response ..
>
>Regards
>Nebu
>
>
>Need a new email address that people can remember
>Check out the new EudoraMail at
>http://www.eudoramail.com
>
>



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