How to do parallel testing with peekpoketester in chisel3?

Question

I want to write a bus monitor for my design in chisel3 (actually a mdio bus) and I wonder if it's possible to execute this monitor function in parallel to the "main" testbench. Like we do it in cocotb with cocotb.fork() coroutine ?

Answer 1

There is no support for parallel testing with chisel3.iotesters ("Chisel Testers"). However, there is support for parallel testing with the new testing framework: chisel3.testers ("Chisel Testers2").

This adds support for fork, join, and parallel constructs. A concise example is testing a queue by forking both the enqueueing and dequeueing:

it should "work with a combinational queue" in {
  test(new PassthroughQueue(UInt(8.W))) { c =>
    c.in.initSource()
    c.in.setSourceClock(c.clock)
    c.out.initSink()
    c.out.setSinkClock(c.clock)

    fork {
      c.in.enqueueSeq(Seq(42.U, 43.U, 44.U))
    }.fork {
      c.out.expectDequeueSeq(Seq(42.U, 43.U, 44.U))
    }.join()
  }
}

For an additional example, see the chisel-template file GcdTesters2.scala.