for cAS before  RAS:

CAS goes low, wait, RAS goes low, wait a bit longer, RAS goes high, CAS goes
high. The DRAM has internal refresh counters, and doing the cas, ras
sequence triggers the refresh cycle.

----- Original Message -----
From: "Tony Nixon"


> Hi all,
>
> Has anyone got some knowledge of CAS before RAS refresh?
>
> Does CAS go LOW, then RAS gets cycled for each ROM address, then CAS
> goes HIGH again?

I think that is a hidden refresh, and not all dram supports it.

--
Jon Baker

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