Hardware/software co-design

Hardware/software co-design, or HW/SW co-design, is a system-level approach where hardware and software are created together instead of separately. The aim is to improve overall system qualities like speed, energy use, cost, and adaptability by experimenting with different ways to divide tasks between hardware and software early in the design process. This method is common in embedded systems, cyber-physical systems, and heterogeneous computing platforms, where software processing and hardware acceleration must operate closely together.

Overview

The core idea is that hardware and software constraints are weighed simultaneously, so choices on one side account for the other. A function can be implemented as software running on a processor or as dedicated hardware logic, each option affecting performance, power, chip area, and cost.

By keeping both possibilities open early on, co-design can find combinations that a single-sided approach would overlook. The boundary between hardware and software is treated as a design variable: computationally intensive, regular tasks get dedicated hardware, while control logic and changeable parts stay in software. Parameters like bit widths, buffer sizes, and parallelism are shared between both sides rather than set independently.

History

Co-design emerged in the late 1980s and early 1990s, as embedded systems grew more complex and the old practice of designing hardware and software separately became unworkable. Early products like telecom gear, industrial controllers, and consumer electronics faced tight performance and power limits that software tuning alone couldn't meet. Initial research focused on designing digital hardware and embedded software together, allowing a function to be placed either on a processor or in custom logic.

Formal methods for partitioning, system-level specification, and performance estimation were developed, and electronic design automation tools began supporting these combined workflows. During the 1990s, co-design became closely linked to embedded systems and system-on-chip design, as integrating processors, memory, peripherals, and custom logic onto a single chip made joint design necessary for hitting cost, performance, and power targets.