Digital Spectrometer Generator designed in Chisel HDL

Overview

This repository contains digital spectrometer generator designed in Chisel hardware design language. Two major modules SpectrometerVanilla and SpectrometerTest accompanied with appropriate tests are explained in the text below.

SpectrometerVanilla

Block diagram of the SpectrometerVanillamodule (check SpectrometerVanilla.scala inside src/main/scala ) is given bellow.

SpectrometerVanillaconsists of the following Chisel generators (available inside generators directory and organized as submodules):

Piecewise Linear Function Generator PLFG
Numerically Controlled Oscillator NCO
Single-path Delay Feedback Fast Fourier Transform accelerator SDF-FFT
Logarithm-Magnitude circuitry LogMagMux
Spectral Accumulator accumulator

Parameters and address space of the each block from presented diagram can be customised inside SpectrometerVanillaParameters case class.

SpectrometerTest

Block diagram of the SpectrometerTestmodule (check SpectrometerTest.scala inside src/main/scala ) is given bellow.

Besides generators mentioned in the previous paragraph, this system comprises following blocks:

UART transmitter and UART receiver written in Chisel3 (available inside directory generators/uart) and mostly taken from sifive-blocks.
A lot of AXI4-stream splitters (check generators/splitter)
A lot of AXI4-stream multiplexers, AXI4-stream adapters and AXI4/AXI4-stream buffers are extensively used which together with AXI4-stream splitters make easier to test whole system. Those modules are available inside rocket directory of the dsptools library.
Blocks always_ready, all_ones and all_zeroswhich are self-explanatory.

Parameters for all generators, as well as address space for the each module separately, can be customized inside SpectrometerTestParameters class.

Prerequisites

The following software packages should be installed prior to running this project:

Setup

Generate verilog

Clone this repository and switch directory:

git clone https://github.com/milovanovic/spectrometer.git
cd spectrometer

Both SpectrometerTest and SpectrometerVanilla scala files contains object used for verilog generation:

// replace ModuleName with SpectrometerVanilla or SpectrometerTest

object ModuleNameApp extends App {
  implicit val p: Parameters = Parameters.empty
  // define parameters of the spectrometer
  val params = ... 
  
  val standaloneModule = LazyModule(new ModuleName(params) with ModuleNamePins)
  
  // generate verilog code of the standaloneModule with parameters described inside params
  chisel3.Driver.execute(args,()=>new ModuleName(params))
  
  // or use new chisel3 command which uses *ChiselStage
  (new chisel3.stage.ChiselStage).execute(
    Array("-X", "verilog"),
    Seq(ChiselGeneratorAnnotation(() => new ModuleName(params))))
}

Note: *ChiselStage To run specific App and generate verilog, type in console next command:

sbt "runMain spectrometer.ModuleNameApp"

By selecting specific options inside chisel3 driver or stage, user can customize exact directory where verilog code is going to be generated.

Running tests

For running tests, clone this repository, switch directory and run all tests:

git clone https://github.com/milovanovic/spectrometer.git
cd spectrometer
sbt test

Travis

Each new commit execute sbt "testOnly spectrometer.SpectrometerTestSpec" command inside Travis CI.

Tests

Tests for the digital spectrometer are loacated in src/test/scala directory. These tests, as well as the other structures needed for running them, are defined in the following files:

SpectrometerTestSpec.scala and SpectrometerVanillaSpec.scala - various test cases can be find for both SpectrometerVanilla and SpectrometerTest modules.
A lot of testers defined in *SpectrometerTesters.scala files which content is more or less self-explanatory by the name of the scala file which contains appropriate tester.
SpectrometerTesterUtils.scala - contains a lot of useful helper functions for testers such as getTone, checkFFTerror, axi4 stream format functions, plot functions etc.

For proper register initialization and streaming transactions inside tests, AXI4MasterModel and AXI4StreamModel are extensively used, both available as a part of dsptools library.