| Constructing Hardware in a Scala Embedded Language (Chisel) | |
|---|---|
Logo.svg){kind=small} | |
| Paradigms | Multi-paradigm: concurrent, functional, imperative, object-oriented |
| Family | Scala |
| Developer | University of California, Berkeley |
| First appeared | June 2012 |
| Stable release | 7.6.0
/ December 20, 2025 |
| Typing discipline | Inferred, static, strong, structural |
| Scope | Lexical (static) |
| Implementation language | Scala |
| Platform | Java virtual machine (JVM) JavaScript (Scala.js) LLVM (Scala Native) (experimental) |
| License | Apache License 2.0 |
| Website | www |
Chisel (an acronym for Constructing Hardware in a Scala Embedded Language[1]) is an open-source hardware description language (HDL) used to describe digital electronics and circuits at the register-transfer level.[2][3]
Chisel is based on Scala as a domain-specific language (DSL). Chisel inherits the object-oriented and functional programming aspects of Scala for describing digital hardware. Using Scala as a basis allows describing circuit generators. High quality, free access documentation exists in several languages.[4]
Circuits described in Chisel can be converted to a description in Verilog for synthesis and simulation.
Code examples
editA simple example describing an adder circuit and showing the organization of components in Module with input and output ports:
class Add extends Module {
val io = IO(new Bundle {
val a = Input(UInt(8.W))
val b = Input(UInt(8.W))
val y = Output(UInt(8.W))
})
io.y := io.a + io.b
}
A 32-bit register with a reset value of 0:
val reg = RegInit(0.U(32.W))
A multiplexer is part of the Chisel library:
val result = Mux(sel, a, b)
Use
editAlthough Chisel is not yet a mainstream hardware description language, it has been explored by several companies and institutions. The most prominent use of Chisel is an implementation of the RISC-V instruction set, the open-source Rocket chip.[5] Chisel is mentioned by the Defense Advanced Research Projects Agency (DARPA) as a technology to improve the efficiency of electronic design, where smaller design teams do larger designs.[6] Google has used Chisel to develop a Tensor Processing Unit for edge computing.[7] Some developers prefer Chisel as it requires one-fifth as much code and is much faster to develop than Verilog.[8]
Circuits described in Chisel can be converted to a description in Verilog for synthesis and simulation using a program named FIRRTL.[9][better source needed]
See also
edit
References
edit- ^ Bachrach, J.; Vo, H.; Richards, B.; Lee, Y.; Waterman, A.; Avižienis, R.; Wawrzynek, J.; Asanović, K. (June 2012). "Chisel: constructing hardware in a Scala embedded language". Proceedings of the 49th Annual Design Automation Conference (DAC 2012). San Francisco, California, US: Association for Computing Machinery (ACM). pp. 1216–25. doi:10.1145/2228360.2228584. ISBN 978-1-4503-1199-1.
- ^ "Chisel". people.eecs.berkeley.edu. California, U.S.: University of California, Berkeley. Archived from the original on 2021-10-16. Retrieved 2020-07-08.
- ^ Bachrach, Jonathan (ed.). "Chisel: Accelerating Hardware Design" (PDF). RISC-V. California, U.S.: RISC-V International.
- ^ Schoeberl, Martin (August 30, 2019). Digital Design with Chisel (in English, Chinese, Japanese, and Vietnamese) (2nd ed.). Kindle Direct Publishing. ISBN 978-1689336031.
- ^ Asanović, Krste; et al. "rocket-chip". GitHub. RISC-V International. Retrieved 11 November 2016.
- ^ Moore, Samuel K. (2018-07-16). "DARPA Plans a Major Remake of U.S. Electronics". IEEE Spectrum. Institute of Electrical and Electronics Engineers (IEEE). Retrieved 2020-06-10.
- ^ Derek Lockhart, Stephen Twigg, Ravi Narayanaswami, Jeremy Coriell, Uday Dasari, Richard Ho, Doug Hogberg, George Huang, Anand Kane, Chintan Kaur, Tao Liu, Adriana Maggiore, Kevin Townsend, Emre Tuncer (2018-11-16). Experiences Building Edge TPU with Chisel. Retrieved 2020-06-10.
- ^ "XiangShan open-source 64-bit RISC-V processor to rival Arm Cortex-A76 - CNX Software". CNX Software - Embedded Systems News. 2021-07-05. Retrieved 2022-03-26.
- ^ "Chisel/FIRRTL Hardware Compiler Framework". Retrieved 2022-09-08.
