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Re: [microblaze-uclinux] SDRAM and Flash memories sharing the same pins



I've been bitten by shared signals between SDRAM and flash busses, but
solved (worked around) the problem by switching to a board that has
completely separate busses.  Generally better if at all possible.

My issue was due to some shared control signals - not A/D busses.  I
know that the Suzaku board has some creative custom logic in there to
handle some level of muxing SDRAM and flash busses - would be worth a
look to see if it'd apply in your case.

Steve

--- Ronaldo Valiati <rvaliati@pd3.com.br> wrote:

> Hi all,
> 
> I'm starting in the Microblaze-uClinux world with a custom XC3S1000 
> board and in this board the SDRAM and Flash data and address buses
> share 
> the same IO pins in the FPGA. As SDRAM and Flash use different memory
> 
> controllers I need to insert some misc logic to multiplex the signals
> 
> that come from the memories controllers to the external pins. I
> already 
> tried to insert this logic but had some problens with the
> bidirectional 
> data buses from the controllers that can only be associated with 
> external pins.
> I also tried to work with the Mem_DQ_I,  Mem_DQ_O and  Mem_DQ_T from
> the 
> opc_emc controller but in this case the wrapper generated by the EDK 
> fails in the synthesis process.
> Did someone already implemented some kind of hardware to share the
> same 
> IO pins to access SDRAM and Flash? I would be very glad in hear some
> tips.
> 
> Thanks and regards,
> 
> -- 
> Ronaldo Valiati
> Engenheiro de Projetos
> rvaliati@pd3.com.br
> Fone: +55 51 33371227
> 
> 
> 
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> 
> 

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