<[email protected]> wrote in message
news:[email protected] oups.com...
> Hi,
>
> I'm trying to control a SDR SDRAM (Micron 64Mbit chip) using an Altera
> DE2 board. I've gotten the hardware interface squared away (thanks
> everyone for your help!).
>
> Now it's the tricky stuff. Any one have an idea how I can change the
> refresh rate while the RAM is in operation?
>
The most obvious question would be 'Why?'

> I have the DRAM interface built using the SOPC builder that comes with
> Quartus II using the NIOS II system.
>
That will limit your options (as would probably most other vendor IP DRAM
controllers).

> I know you can change the refresh rate during the build but I need a
> way to change the refresh rate during operation. The only thing I can
> think of is maybe change the clock speed? I have it running off a
> 50Mhz clock....
>
A simpler way would be to simply have a DRAM controller that has an explicit
'Refresh Request' input that would cause the controller to perform a
refresh. Then connect that input up to any programmable timer or other
logic that you would like to use. Changing the clock rate would be far down
on my list of ways to accomplish your goal....but again, it begs the
original question about why you would want to change the refresh rate
dynamically at all.

KJ