|Description:||Functional hardware description language|
|CλaSH Liaison:||Richard Tobias|
1 What is CλaSH
CλaSH (pronounced ‘clash’) is a functional hardware description language that borrows both its syntax and semantics from the functional programming language Haskell. It provides a familiar structural design approach to both combinational and synchronous sequential circuits. The CλaSH compiler transforms these high-level descriptions to low-level synthesizable VHDL, Verilog, or SystemVerilog.
Features of CλaSH:
- Strongly typed, but with a very high degree of type inference, enabling both safe and fast prototyping using concise descriptions.
- Interactive REPL: load your designs in an interpreter and easily test all your component without needing to setup a test bench.
- Compile your designs for fast simulation.
- Higher-order functions, in combination with type inference, result in designs that are fully parametric by default.
- Synchronous sequential circuit design based on streams of values, called Signals, lead to natural descriptions of feedback loops.
- Multiple clock domains, with type safe clock domain crossing.
- Template language for introducing new VHDL/(System)Verilog primitives.
From the CλaSH website http://www.clash-lang.org/
2 CλaSH Project Ideas
Christiaan Baaij, one of the principle creators of CλaSH gave these ideas for hackathon projects:
- Building a small CPU is always fun I. Perhaps build one that can do: http://icfpc2011.blogspot.nl/2011/06/task-description-contest-starts-now.html?m=1
- Or set it to dim lights that show the slowly diminishing state of each of the processors memory.
- Or if you don't have enough leds, make a small vga driver (most forgiving display protocol)
A project that I'm think about is:
- To get a decent build system for CλaSH that includes regression testing with a verilog simulator and calling the appropriate EDA tools from either Altera or Xilinx to synthesize, place and route and then download the bitfile to the FPGA itself. A good starting point for this is the build system that Austin Seipp created in his claap project. You can find this build system inside of his project at https://github.com/thoughtpolice/claap.
3 Good FPGA Boards to Bring to BayHac2017 CλaSH Hackathon
I will bring a few DE0-nano boards to the hackathon. They are quite inexpensive and can be purchased for about $85 on DigiKey https://www.digikey.com/products/en?mpart=P0082&v=771, adafruit https://www.adafruit.com/products/451 and other locations on the web.
A good list of boards can be found here: https://www.reddit.com/r/haskell/comments/5opec9/haskell_to_hardware_project_clash_701_released/
The list is copied here (thanks goes to darchon on the subreddit for haskell):
- DE1-SoC (http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=167&No=836)
- SoCKit (http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=167&No=816)
- DE0-nano (http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=139&No=593)
- DE1 (http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=53&No=83)