Knowledge Base Article
The nonvolatile cells in an nvSRAM are delivered from Cypress with 0x00 written in the cells.However, incoming inspection routines at customer or contract manufacturer’s sites, sometimes, reprogram these values. Final NV patterns are typically repeating patterns of AA, 55, 00, FF, A5, or 5A. End product’s firmware should not assume an NV array is in a set programmed state. Routines that check memory content values to determine first time system configuration and cold or warm boot status, should always program a unique NV pattern (for example, a complex 4-byte pattern of 46 E6 49 53 hex or more random bytes) as part of the final system manufacturing test to ensure these system routines work consistently.