Testbench functions for circuits

Compares the first two Signals for equality and logs a warning when they are not equal. The second Signal is considered the expected value. This function simply returns the third Signal unaltered as its result. This function is used by outputVerifier.

NB: This function can be used in synthesizable designs.

The same as assert, but can handle don't care bits in it's expected value.

Ignore signal for a number of cycles, while outputting a static value.

Example:

testInput
  :: KnownDomain dom
  => Clock dom
  -> Reset dom
  -> Signal dom Int
testInput clk rst = stimuliGenerator clk rst $(listToVecTH [(1::Int),3..21])

>>> sampleN 14 (testInput systemClockGen resetGen)
[1,1,3,5,7,9,11,13,15,17,19,21,21,21]

Clock generator to be used in the testBench function.

To be used like:

clkSystem en = tbClockGen @System en

Example

module Example where

import Clash.Explicit.Prelude
import Clash.Explicit.Testbench

-- Fast domain: twice as fast as "Slow"
createDomain vSystem{vName="Fast", vPeriod=10}

-- Slow domain: twice as slow as Fast
createDomain vSystem{vName="Slow", vPeriod=20}

topEntity
  :: Clock "Fast"
  -> Reset "Fast"
  -> Enable "Fast"
  -> Clock "Slow"
  -> Signal "Fast" (Unsigned 8)
  -> Signal "Slow" (Unsigned 8, Unsigned 8)
topEntity clk1 rst1 en1 clk2 i =
  let h = register clk1 rst1 en1 0 (register clk1 rst1 en1 0 i)
      l = register clk1 rst1 en1 0 i
  in  unsafeSynchronizer clk1 clk2 (bundle (h, l))

testBench
  :: Signal "Slow" Bool
testBench = done
  where
    testInput      = stimuliGenerator clkA1 rstA1 $(listToVecTH [1::Unsigned 8,2,3,4,5,6,7,8])
    expectedOutput = outputVerifier   clkB2 rstB2 $(listToVecTH [(0,0) :: (Unsigned 8, Unsigned 8),(1,2),(3,4),(5,6),(7,8)])
    done           = expectedOutput (topEntity clkA1 rstA1 enableGen clkB2 testInput)
    done'          = not <$> done
    clkA1          = tbClockGen @"Fast" (unsafeSynchronizer clkB2 clkA1 done')
    clkB2          = tbClockGen @"Slow" done'
    rstA1          = resetGen @"Fast"
    rstB2          = resetGen @"Slow"

Enable signal that's always enabled. Because it has a blackbox definition this enable signal is opaque to other blackboxes. It will therefore never be optimized away.

Clock generator for the System clock domain.

NB: can be used in the testBench function

Example

topEntity :: Vec 2 (Vec 3 (Unsigned 8)) -> Vec 6 (Unsigned 8)
topEntity = concat

testBench :: Signal System Bool
testBench = done
  where
    testInput      = pure ((1 :> 2 :> 3 :> Nil) :> (4 :> 5 :> 6 :> Nil) :> Nil)
    expectedOutput = outputVerifier ((1:>2:>3:>4:>5:>6:>Nil):>Nil)
    done           = exposeClockResetEnable (expectedOutput (topEntity $ testInput)) clk rst
    clk            = tbSystemClockGen (not <$> done)
    rst            = systemResetGen

Compare a signal (coming from a circuit) to a vector of samples. If a sample from the signal is not equal to the corresponding sample in the vector, print to stderr and continue testing. This function is synthesizable in the sense that HDL simulators will run it.

Example:

expectedOutput
  :: Clock dom -> Reset dom
  -> Signal dom Int -> Signal dom Bool
expectedOutput clk rst = outputVerifier clk rst $(listToVecTH ([70,99,2,3,4,5,7,8,9,10]::[Int]))

>>> import qualified Data.List as List
>>> sampleN 12 (expectedOutput systemClockGen resetGen (fromList (0:[0..10] List.++ [10,10,10])))

cycle(<Clock: System>): 0, outputVerifier
expected value: 70, not equal to actual value: 0
[False
cycle(<Clock: System>): 1, outputVerifier
expected value: 70, not equal to actual value: 0
,False
cycle(<Clock: System>): 2, outputVerifier
expected value: 99, not equal to actual value: 1
,False,False,False,False,False
cycle(<Clock: System>): 7, outputVerifier
expected value: 7, not equal to actual value: 6
,False
cycle(<Clock: System>): 8, outputVerifier
expected value: 8, not equal to actual value: 7
,False
cycle(<Clock: System>): 9, outputVerifier
expected value: 9, not equal to actual value: 8
,False
cycle(<Clock: System>): 10, outputVerifier
expected value: 10, not equal to actual value: 9
,False,True]

If your working with BitVectors containing don't care bits you should use outputVerifierBitVector.

Same as outputVerifier but used in cases where the testbench domain and the domain of the circuit under test are the same.

Same as outputVerifier, but can handle don't care bits in it's expected values.

Same as outputVerifier', but can handle don't care bits in it's expected values.

Same as tbClockGen, but returns two clocks on potentially different domains. To be used in situations where the circuit under test runs in a different domain than the circuit testing it. Most commonly used to test synchronous circuits (with an asynchronous test circuit).