Re: How to configure MDREFR on StrongARM SA-1110

[Russell K. - A. L. <li...@ar...>]

On Mon, Oct 14, 2002 at 11:26:58AM +0200, Abraham vd Merwe wrote:
> That's what I gathered. However in the SDRAM SPD (Serial Presence Detect -
> the little EEPROM which contains the info about the DIMM) module, the
> refresh time goes from 3.9us up to 125us which is orders of magnitude
> shorter than all the other refresh times I've seen.

64ms / 4096 = ~15us

> So I've thought that the XXms refresh times was for all the rows

Correct - you'll find this confirmed by data sheets on the actual SDRAM
devices.

> and that the SPD specs has it per row, but the explanation above throws
> that theory out the door. Do you think
> it is possible that the SDRAM dimms can have such short refresh times?

No.  Or if they do, the refresh starts severely impacting on the
performance of the device.

> Also, do those row address bits in above calculation include bits for the
> bank selects or is it just the row address bits on the dimm (I guess it's
> the latter right?)

tbh I don't remember off hand.  I seem to remember that it doesn't
include the bank selects, but please check the data on the SDRAM
chips you're using there.