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Problem with SDRAM SAMSUNG K4S511632D-UC75

Started by oe1gca September 10, 2008
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