SystemC/TLM Controller for Efficient NAND Flash Management in Electronic Musical Instruments

The design of an efficient memory subsystem is a fundamentally challenging task in the design of electronic equipment. The storage hierarchy chosen for a particular design has a significant impact on the overall performance and cost. Flash memory often contains the boot code, operating system kernel, device drivers, middleware, and other application-specific software that can result in megabytes of non-volatile stored data. To maximize the performance, data are moved from non-volatile memory to faster SDRAM (synchronous dynamic random-access memory). Non-volatile memory technologies reach a performance level close to that of dynamic RAMs with the additional benefit of persistent data storage. When cost is critical, an approach where the data are managed directly from non-volatile memory can be used. In this case the non-volatile memory subsystem is constantly accessed to retrieve data. The deep understanding of the system architecture is critical to identify any factor that affects memory performance and the resulting system performance; particularly in specific applications with stricter requests like streaming audio when more than one hundred data streams must be handled in a real-time environment and sound must be generated with a total latency of a few milliseconds. This article reports the development of the system-level model of a controller in a SystemC simulation environment capable of optimizing the use of NAND type flash memories for storage and playback of audio samples in real-time music applications, with the aim of reducing the quantity of the system SDRAM memory, thus lowering the cost of the final product, while still providing the most high-fidelity sound experience