Problem with SDRAM SAMSUNG K4S511632D-UC75

Hi!

With our current SDRAM initialization (in our boot code), sometimes the
SDRAM does not work correctly after power-up reset. Every second quad-word
can't be accessed (it seems that it can't be written).

When the SDRAM is in this erroneous state after power-up, repetitive
resets (not power-up) won't resolve the problem. Only a power-off/on cycle
will resolve the problem.

So I think, something is missing or wrong in the initialization sequence.

We are using a Technologic Systems TS-7200 board with an EP9302 CPU.
The initialization code we took is from the Open TS-72XX system boot
code.

The datasheet of the SDRAM does not cover the initialization sequence.


Any ideas?


Thank you in advance!
Gerhard

"oe1gca" <g.chvatal@adcon.at> wrote in message 
news:EZCdnQseXbpxhFXVnZ2dnUVZ_rHinZ2d@giganews.com...
> Hi!
>
> With our current SDRAM initialization (in our boot code), sometimes the
> SDRAM does not work correctly after power-up reset. Every second quad-word
> can't be accessed (it seems that it can't be written).
>
> When the SDRAM is in this erroneous state after power-up, repetitive
> resets (not power-up) won't resolve the problem. Only a power-off/on cycle
> will resolve the problem.
>
> So I think, something is missing or wrong in the initialization sequence.
>
> We are using a Technologic Systems TS-7200 board with an EP9302 CPU.
> The initialization code we took is from the Open TS-72XX system boot
> code.
>
> The datasheet of the SDRAM does not cover the initialization sequence.
>
>
> Any ideas?
>
>
> Thank you in advance!
> Gerhard
>
>
>
This seems to be their generic initialization guide.
http://www.samsung.com/global/business/semiconductor/products/dram/downloads/sdr_device_operation_jul_06.pdf

Scott 

On Sep 11, 7:39=A0pm, "Not Really Me"
<sc...@validatedQWERTYsoftware.XYZZY.com> wrote:
> "oe1gca" <g.chva...@adcon.at> wrote in message
>
> news:EZCdnQseXbpxhFXVnZ2dnUVZ_rHinZ2d@giganews.com...
>
> > Hi!
>
> > With our current SDRAM initialization (in our boot code), sometimes the
> > SDRAM does not work correctly after power-up reset. Every second quad-w=
ord
> > can't be accessed (it seems that it can't be written).
>
> > When the SDRAM is in this erroneous state after power-up, repetitive
> > resets (not power-up) won't resolve the problem. Only a power-off/on cy=
cle
> > will resolve the problem.
>
> > So I think, something is missing or wrong in the initialization sequenc=
e.
>
> > We are using a Technologic Systems TS-7200 board with an EP9302 CPU.
> > The initialization code we took is from the Open TS-72XX system boot
> > code.
>
> > The datasheet of the SDRAM does not cover the initialization sequence.
>
> > Any ideas?
>
> > Thank you in advance!
> > Gerhard
>
> This seems to be their generic initialization guide.http://www.samsung.co=
m/global/business/semiconductor/products/dram/do...
>
> Scott

This could very well be a hardware issue on your board. Probe the
board when it goes into the erronous state, check the voltages and
clock.
Look for gliches also