Clash 1.10 is the first release since Rowan Goemans joined QBayLogic as the new Clash lead. This post highlights the removal of Clash.Prelude.DataFlow in favor of clash-protocols, introduces NumConvert, and gives porting guidance.

For years, debugging Clash designs in a waveform viewer has been a massive pain. After all, the waveform viewers we have were not designed with Clash in mind, and glady present us with unintelligible binary values. But those times are now over! I’ve spent the last months working on Shockwaves, a system that lets you show typed waveforms in (Surfer)[https://surfer-project.org/], and after many, many changes, tests, bug fixes and rewrites, we have finally reached the point of an official release!

GHC’s builtin overflow warnings are easy to bypass and don’t work for custom numeric types. We wrote a GHC source plugin, checked-literals, that rewrites numeric literals so that out-of-range values are rejected at compile time. It works in monomorphic and polymorphic contexts, supports integer and rational literals, and produces actionable error messages – including suggested type-level constraints.

With the introduction of clash-protocols-memmap and clash-bitpackc, it seemed a good idea to create matching BitVec<N>, Unsigned<N>, Signed<N>, and Index<N> types in Rust. Let’s talk about how we can make this happen.

I recently came across a question on /r/haskell, where /u/netj_nsh asked whether Clash supports asynchronous circuit designs. They went on to ask whether designing with multiple, synchronous clock domains is possible. While the (very) short answers are no and yes, respectively, I figured I’d write a blog post clarifying these concepts and how they relate to Clash. Mostly though, I just wanted an excuse to write about Clash’s simple yet clever trick that makes it tick: Signal.

Using a stack project template you can easily set up a new project for the Arrow DECA development board which contains an Intel MAX10 FPGA (50K LEs; 1638 Kbit memory) and a lot of peripherals (10/100 Mbps EtherNet; HDMI TX; USB 2.0 PHY; audio CODEC; etc). The project template contains and LED-blinker created in Clash and a Quartus project that automatically loads the Clash generated files.

We’ve just released Clash 1.4 to the world. We’ve summarized the most important changes in this blogpost.

Last Friday we released Clash 1.2.2 on GitHub. In big part thanks to our lovely community, we’ve found and fixed many bugs. Thanks to some patches, Clash even runs anywhere from 2-20% faster for some common design patterns! With this blogpost I’d like to highlight some of the progress we’ve made since the 1.2 release, and elaborate on our future plans.

As promised when releasing 1.0, we’ve tried our best to keep the API stable. We think most designs will continue to compile with this new version, although special care needs to be taken when using:

• ..inline blackboxes. Instead of taking a single HDL, inline primitives now take multiple. For example, InlinePrimitive VHDL ".." must now be written as InlinePrimitive [VHDL] "..".

• ..the Enum instance for BitVector, Index, Signed, or Unsigned, as they now respect their maxBound. See #1089.

It’s here! Clash 1.0 is finally released! And it has a binary release for the very first time! Check out the install instructions instructions on how to get it!

10 years old

First a short retrospective: the very first demonstration of the Clash compiler was given on the 3rd of September 2009 at the Haskell'09 Symposium in Edinburgh:

We were planning the 1.0 release of Clash for some time now, but decided that such a momentous occasion should coincide with the 10 year anniversary of Clash (+1 day due to release engineering mishaps). We really want to thank all of our contributors for their continued support of Clash. The code contributors that invest their time to create new features and fix bugs, and the financial contributors that enable the core Clash developers to work on Clash as their day job. Much praise for our users as well, who’ve struggled through our API changes over the years (which should happen much, much, less from now on), who helped us pinpoint many bugs and thus making Clash a more stable piece of software.