AN302 - F-RAM™ SPI Read and Write Internal Operation and Data Protection

AN302 discusses the importance of keeping HIGH during power transitions and suggests a circuit to accomplish this. It also describes the internal operation of Cypress's high-speed SPI F-RAM devices during memory read & write operations

Overview

Ferroelectric random access memory (F-RAM) is a nonvolatile memory that uses a ferroelectric technology for storing data. The SPI F-RAM scores over other nonvolatile serial memory options due to its fast write speed and endurance (the number of writes that can be done before damaging the F-RAM’s nonvolatile cells). Hundreds of bytes can be written in tens of microseconds. EEPROM and flash memories require tens of milliseconds to do the same. Writing data quickly before losing power is particularly useful in systems that require preserving machine state information, parameter settings, or other vital data in a power-down event. To preserve data make certain to control signals at both power up and power down.