[U-Boot] [PATCH] arm: at91sam9n12: change EBI IO to high drive mode

[Bo Shen]

Hi Andreas,

On 07/21/2013 07:02 AM, Andreas Bießmann wrote:
> To answer the second question we can have a look at the specs. I can
> presume by looking at the specs that we need to switch the drive
> strength for the data I/O pins to higher level for this board to fix the
> problem mentioned in the commit message. You have to know that this
> specific part (configuring EBI for NAND access) is copied from board to
> board (yes, another point to consolidate in near future). And this
> specific part is copied over from at91samx5ek which seems to work with
> lower drive strength. Unfortunately the concrete limit of EBI
> capacitance is not specified in specs for at91sam9n12 nor at91sam9x35
> devices. More distracting this parameter (EBI_DRIVE) seems to have
> different reset values in at91sam9n12 and atsam9x35 devices, at least
> the specs say so ... Atmel guys, please have a look on that and update
> your specs!
> Especially fill the TBD field in at91sam9n12 spec p. 311 (EBI_DRIVE in
> CCFG_EBICSA) in version 11063I–ATARM–17-Apr-13. And possibly check why
> there is EBI_DRIVE default to 'low' for 9x5 and default to 'high' for
> 9n12. There is also another bug in the specs, when you have to decide
> between 'high' and 'low' you cant say the 'low' is required for
> 'capacitance < TBD pF' and 'high' is required for 'capacitance < TBD
> pF', presumably the 'high' part should be chosen for 'capacitance > TBD pF'.

Thank for this information, I will check this with our colleagues.
Thanks again.

> So from my point of view this patch fixes an existing bug in a new board
> introduced in this releases MW. It uses a fairly new SoC which is first
> used in this new board. Therefore
>
> Acked-by: Andreas Bießmann<andreas.devel at googlemail.com>
>
> And Tom, please apply this patch directly.
>
> Best regards
>
> Andreas Bießmann

Best Regards,
Bo Shen