2.1 Ferroelectric RAM (FRAM) Overview

Using FRAM nonvolatile memory is very similar to using static RAM (SRAM). FRAM's first introduction as an embedded memory in a general-purpose ultra-low power MCU was on Texas Instruments 16-bit MSP430 product line, the MSP430FR57xx family.

Some of the key attributes of FRAM are:

• FRAM is nonvolatile; that is, it retains its contents on loss of power.
• The embedded FRAM on MSP430 devices can be accessed (read or write) at up to a maximum speed of 8 MHz. Above 8 MHz, wait states are used when accessing FRAM.
• Writing to FRAM and reading from FRAM requires no setup or preparation such as pre-erase before write or unlocking of control registers (unless the MPU is used to protect the FRAM against write access).
• FRAM is not segmented and each bit is individually erasable, writable, and addressable.
• FRAM segments do not require an erase before a write.
• FRAM write accesses are low power, because writing to FRAM does not require a charge pump.
• FRAM writes can be performed across the full voltage range of the device.
• FRAM write speeds can reach up to 8 MBps with a typical write speed of approximately 2 MBps. The high speed of writes is inherent to the technology and aided by the elimination of the erase bottleneck that is prevalent in other nonvolatile memory technologies ^[8]. In comparison, typical MSP430 flash write speed including the erase time is approximately 14 kBps ^[7].