Software store and  toggling  of OE signal for Simtek and Cypress NVSRAM's

Question:

How does the Software store work for Simtek parts? Can the chip clock the address without OE signal? Is the behavior different for Simtek and Cypress NVSRAM's?

 

Answer:

 

 Software store operation executes only after six valid addresses are toggled with respect to CE. These address sequences are valid only when it is generated while write enable is disabled (WE is high for all six sequences). In case of Simtek parts (Part numbers starting with STK) It is not necessarily a read operation and thus toggling OE is optional. In case of OE controlled read, OE and CE both should toggle. However for Cypress NVSRAM ( Parts starting with CY14) OE should be toggled and six valid read for a software store to happen.