HCC Embedded has developed what it says is an advanced file system architecture for solid state memory that is custom designed for the needs of smart-energy and smart-meter applications.
According to the company, their approach maximizes the life of flash, significantly reduces power consumption, and provides a deterministic ‘emergency write’ function, which reduces cost by allowing the on-board capacitor to be as small as possible.
Collectively the file-system features can result in savings of many ‘cents’ for each meter, a highly significant cost reduction in high volume manufacture. Moreover, the software the company has developed is “rigorously compliant,” with the MISRA C:2004 coding standard.
The HCC ‘Smart-meter File System (SMFS) requires less than 15kB program memory and less than 1.5kB of RAM on most 32-bit MCUs.
The company's approach takes into account that most metering applications work with well-defined records that are more suited to a database approach. However, general-purpose file systems do not have any cyclic buffer logic for storing records which adds complexity to applications.
Instead, the company developers designed SMFS with a structured database to reduce complexity of the application and improve the performance of the system in almost every way—speed, power consumption, and flash life.
Because of the nature of the smart meter designs it is targeting, HCC Embedded's also incorprates a number of other important capabilities, including 1) Fail-safe data storage for guaranteed system recovery, 2) Persistent data storage for 15 years or more: 3) mechanisms to minimize the number of flash operations to preserve both the flash and the battery; and most importantly, 4) Deterministic behavior in the event of unexpected reset.