Subject: 64-bit Data Flash Access Problem [MPC8245]

From: "Augustine Nebu Philips" <[email-masked]>
Date: Wed, 24 Sep 2003 12:04:41 -0500

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

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