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FRAM Microcontroller Targets Low Power Applications

March 2, 2012

Texas Instrument's 16-bit MSP430FR58xx Wolverine series gains some of its low power characteristics because it uses a unified FRAM storage for code and data.

William G. Wong

Texas Instrument's (TI) 16-bit MSP430FR58xx Wolverine series (Fig. 1) gains some of its low power characteristics because it uses a unified FRAM storage for code and data. FRAM consumes 1/250th of power when writing compared to flash memory and it is guaranteed to at least 10¹⁵ cycles. Actually TI is still running lifecycle test so this number is what they have hit so far.

Fig. 1: 16-bit MSP430FR58xx Wolverine series uses FRAM for code and data.

MSP430FR58xx is the follow on to the first all FRAM product, the MSP430FR57xx (see Microcontroller Utilizes FRAM For Code And Data). The latets incarnation brings even more memory and better power usage characteristics. It has cut power requirements in half and has a constant power drain regardless of ambient temperature. There is a 10x improvement in leakage current compared to the regulard MSP430 along with a 15% decrease in active power. Standby current is only 360nA. While active, the MSP430FR58xx needs only 100μA/MHz. The on-chip ADC only uses 75μA.

The chip has a fast 6.5μs wakeup time and this is complemented by data in FRAM because it does not need to be saved and restored like normal RAM. Like the MSP430FR57xx, the FRAM is used for code and data. There split is arbitrary providing significantly more flexibility in design compared to flash-based solutions. FRAM has significant benefits in remote program updates as well since writing is a trivial operation compared to banked flash updates.

The chip is supported by an array of software including TI's Eclipse-based Code Composer Studio (CCS) and tools like the Grace configuration program (see Graceful Configuration For MSP430). The debugger incorporates ultra low power optimization rules that can provide examples of how to improved power utilization. It can also track power utilization. TI is also releasing MSP430Ware. MSP430Ware is a collection design resources including application notes and code examples accessible via CCS.

FRAM gives TI a significant edge in this space. Hopefully it will show up in TI's higher end micros as well like the 32-bit Stellaris and C2000 series. FRAM is particular useful in data logging, wireless and mobile applications where fast FRAM updates benefit from it low power requirments. As noted, the ability to wake up quickly and go back to sleep quickly is augmented by the lack of unneccessary RAM restore and save operations.