1 Reply Latest reply on May 19, 2011 3:28 AM by ravi.prakash

    NvSRAM  RWI Inhibit vs WE line

    maged.almawri

      I have a Question about the RWI Inhibit in the Datasheet.   Is that an internal Inhibit, or is it  controlled by the WE what is the relationship?  If WE is not up the first 20 ms, what is the probability of having corrupted data.   Can you elaborate more on that relatinoship.  

        • 1. Re: NvSRAM  RWI Inhibit vs WE line
          ravi.prakash

          Hi Maged,

             

          RWI is an internal inhibit. It is not controlled by WE/. During RWI, condition of WE/ pin or any other control pin has no relevance. And hence, data cannot be corrupted by any means during RWI. Only at the end of the RWI, the WE/ condition will matter. Therefore, we suggest a pull up on WE/ pin to ensure that unwanted writes do not happen after RWI is enabled (and the controller is still booting up).

             

          Thanks

             

          Ravi

             

          Note: To state the obvious, the pull up helps only if the controller IO is in tristate when nvSRAM has completed boot up - at end of tHRECALL - and not if it is in LOW state. Also, you can see that instead of WE/ you can ensure CE/ is HIGH which would have the same effect since any unintended write can happen only if both CE/ and WE/ see a LOW condition at the pins.