Spade

Spade is a hardware description language that draws inspiration from modern software languages to make hardware development more productive, more fun, and less error-prone. A big part of what makes this possible is the type system which helps prevent bugs and makes the code more maintainable.

A common source of errors in hardware designs is clock domain crossing: signals should never cross domains accidentally, and when they do cross, it must be done correctly. Failures to correctly cross domains leads to intermittent problems that can take significant effort to find and fix. By making the language and compiler aware of clock domains through the type system, we will be able to detect and warn programmers about accidental clock domain crossings at compile time. We will to do this in an ergonomic way, where the user only has to specify clock domains on module inputs and outputs with the compiler being able to infer the rest. In addition, the default case of a module that only spans a single domain should not require any explicit domain information form the user to avoid unnecessary verbosity.