[U-Boot-Users] Mirrorbit flashes

Wolfgang Denk wd at denx.de
Fri Jan 23 13:51:58 CET 2004

In message <200401231302.12868.Schramel.Linux at go.bartec.de> you wrote:
> in  flash.h of the U-Boot code there are defined id's for the mirrorbit type AM29LV128M. I 've planed to introduce this flashes for working with my MPC8270.

OK, why not?

> Is this flash the right choice for my cpu (speed)? Is it a big drawback of these flashes that they can't do simultanous writes and reads? 

There are very few flash chips  that  allow  simultaneous  reads  and
writes,  and  even  less software to support it. U-Boot does not need
such a feature, at least.

> Are there any special things to do with u-boot for this flashes ?

Have a look at board/tqm8xx/flash.c for working example code (32  bit
bus, though).

> If i have a soldered flash onboard, my flash configuration will be always the same. Therefore i have no reason to search for other flashes. 

Don't bet on it. It will take less than half a year and you will find
that the flash memory is too small, and yyou want to use bigger flash
chips. Ot it is too big and you  want  to  save  production  cost  by
usiong  smaller  ones.  In  the  end  you  _will_  have several flash
configurations, and you will want to be  able  to  install  the  same
U-Boot image.

> Have I only  to fill up the "flash_info_t"-struct and tune up the erase,write.. -functions? Or there are a lot of more things to do ??

Only flash_info_t needs adjustment, as long as the  flash  chips  are
somewhat "compatible" (i. e. you don't try to use CFI and JEDEC chips
on the same flash bank).

Best regards,

Wolfgang Denk

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Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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