[U-Boot-Users] Can I write to flash using mw command

[bilahari akkiraju]

I did 

 protect off all


I have tried the following command sequences but didnt
succeed in my objective of writing to and erasing
first sector on flash.

WRITE COMMAND SEQUENCE:

  mw ff000555 00AA00AA
  mw ff0002AA 00550055
  mw ff000555 00A000A0
  mw ff000000 12345678
  

SECTOR ERASE COMMAND SEQUENCE:
 
  mw ff000555 00AA00AA
  mw ff0002AA 00550055
  mw ff000555 00800080
  mw ff000555 00AA00AA
  mw ff0002AA 00550055
  mw ff000000 00300030

 Note: I tried mw.b, mw.w, mw.l with appropriate data
but didnt succeed.

In first place is it possible to write to AMD flash
manually like this or shud it be done only
programatically. Any one has tried writing to flash
this way before ( I could write to Intel strata flash
this way). 

 I walked through u-boot code for cfi_flash.c and
flash_write() function that is called when cp (copy)
command is invoked, the code does the same thing, the
only extra thing it does is it polls on data register
bits for a certain amount of time (flash erase, write
timeout intervals) and also does a reset to bring back
device to read array mode 
 
 mw.w ff000000 00F0 ; reset cmd


I have a ppc 8343 processor on board. I am wondering
if U-boot that came with my target board has
configuration that is preventing me to write to flash
(but cp commands works fine with flash). Any one who
has same spansion flash chip s29GL064M can try it, I
cannot figure out the missing link in the chain, any
advise, comments, suggestion will be of great help

Thanks,
Bilahari
   

--- Wolfgang Denk <wd at denx.de> wrote:

> In message
>
<20061005222823.71219.qmail at web33206.mail.mud.yahoo.com>
> you wrote:
> > 
> >  -> I read my board's spec and found out that I
> have
> > two spansion s29GL064M devices on my board whose
> data
> > bus is 16-bit wide and address bus is 32-bit wide.
> > They are attached as 16-bit devices.
> 
> Then your command sequence was wrong.
> 
> >  -> I looked at the data sheet of the spansion
> > s29GL64M
> > and I am sure I am using the right command
> sequences
> > (x16 Mode commands) for erase and program.
> 
> No. In 16 bit mode addresses get shifted by one bit,
> and your command
> word must address both chips, i. e. instead of
> 
> 	mw.b 0xff000555 0xAA
> 
> you need
> 
> 	mw FF000AAA 00AA00AA
> 
> >  -> How can I check if my memory controller is
> > properly  configured or not.
> 
> By carefully studying the hardware documentation,
> processor User's
> manual, chip documentation, etc. Then perform a code
> review.
> 
> Best regards,
> 
> Wolfgang Denk
> 
> -- 
> Software Engineering:  Embedded and Realtime
> Systems,  Embedded Linux
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80
> Email: wd at denx.de
> Do you suppose the reason the ends of the `Intel
> Inside'  logo  don't
> match up is that it was drawn on a Pentium?
> 



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