Chapter 18 - Real-time Fixed-point DSP Firmware

Abstract

There is no absolute definition of what should be considered to be firmware (FW) and what should not, but typically, the definition of firmware is fixed software that runs in an embedded product. It is usually stored in a ROM or EEPROM, but not necessarily. Customers typically do not change the software when using the system. However, there are software that cannot be changed by customers, and they are not firmware. Firmware can be application firmware or system firmware. System firmware is used to manage system hardware and manage other application software. A typical system firmware contains a real-time operating system (RTOS). To implement DSP applications in an embedded product, the total cost of SW design is higher than the total cost of HW design. As a hardware designer, it is essential to minimize the total design cost by supplying good HW. Design of DSP ASIP is HW/SW codesign. Better understanding of SW can enhance cooperative competences for the HW design team. Better understanding of SW design is essential for design of efficient assembly instruction sets. The knowledge gap is large between the basic understanding of DSP theory and the quality design of DSP firmware. There are three aspects to make a good firmware for an application. The first is the knowledge of the application and the skill of application modeling under hardware constraints. The second is the programming technique on finite precision hardware. The third is the real-time programming technique.