[U-Boot-Users] minimum bdi config to read flash on 85xx

[David Hawkins <dwh@ovro.caltech.edu>]

Hi Ben,

> I'm not sure if this has been mentioned or not. 
> You should be able to read/write the flash from
> the BDI-2000, regardless of whether you connect
> the LA or LBA address bits.  The difference comes
> into play when you want to boot from the flash chip.
> During the very early boot process, only the special
> LSbits toggle.

Yeah, I'd read that in some corner of the processor
reference manual, and fired up the MDS board with a
logic analyzer just to confirm it. I wondered at the
time how many people would miss that subtle requirement!

> On one spin of our board we missed this as well, and
> had to do some funny business with an I2C EEPROM to boot
> the board.  Thankfully it was easy with our CPU (MPC8349) 
> because it only involved programming a couple of
> configuration words and no UPM programming like Dave H.
> has suggested.

Ah-ha, so it is possible - cool :)

(crossed fingers it won't happen to me though ...)

> Have you tried asking Freescale for help through their
> website?  I've found their tech support in these matters
> to be responsive and useful.  

Yep, I second that. Freescale's design support is
great. Sometimes they confirm what you don't want to
hear ... but they do respond quickly :)

Cheers,
Dave