diff --git a/src/main/scala/util/SynchronizingReg.scala b/src/main/scala/util/SynchronizingReg.scala index ed0f7bd2..34fc2277 100644 --- a/src/main/scala/util/SynchronizingReg.scala +++ b/src/main/scala/util/SynchronizingReg.scala @@ -12,12 +12,16 @@ import Chisel._ * rather than buffering. * * The 3 different types vary in their reset behavior: + * AsyncResetShiftReg -- This is identical to the AsyncResetSynchronizerShiftReg, + * it is just named differently + * to distinguish its use case. This is a ShiftRegister meant for timing, + * not for synchronization. * AsyncResetSynchronizerShiftReg -- asynchronously reset to 0 * SynchronizerShiftReg -- no reset, pipeline only. * */ -abstract class AbstractSynchronizerReg(w: Int = 1) extends Module { +abstract class AbstractPipelineReg(w: Int = 1) extends Module { val io = new Bundle { val d = UInt(INPUT, width = w) @@ -26,43 +30,57 @@ abstract class AbstractSynchronizerReg(w: Int = 1) extends Module { } -object AbstractSynchronizerReg { +object AbstractPipelineReg { - def apply [T <: Chisel.Data](gen: => AbstractSynchronizerReg, in: T, name: Option[String] = None): T = { - val sync_chain = Module(gen) - name.foreach{ sync_chain.suggestName(_) } - sync_chain.io.d := in.asUInt + def apply [T <: Chisel.Data](gen: => AbstractPipelineReg, in: T, name: Option[String] = None): T = { + val chain = Module(gen) + name.foreach{ chain.suggestName(_) } + chain.io.d := in.asUInt - sync_chain.io.q.asTypeOf(in) + chain.io.q.asTypeOf(in) } } -class AsyncResetSynchronizerShiftReg(w: Int = 1, sync: Int = 3) extends AbstractSynchronizerReg(w) { - require(sync > 0, "Sync must be greater than 0.") +class AsyncResetShiftReg(w: Int = 1, depth: Int = 1, init: Int = 0, name: String = "pipe") extends AbstractPipelineReg(w) { + require(depth > 0, "Depth must be greater than 0.") - override def desiredName = s"AsyncResetSynchronizerShiftReg_w${w}_d${sync}" + override def desiredName = s"AsyncResetShiftReg_w${w}_d${depth}_i${init}" - val syncv = List.tabulate(sync) { i => - Module (new AsyncResetRegVec(w, 0)).suggestName(s"sync_${i}") + val chain = List.tabulate(depth) { i => + Module (new AsyncResetRegVec(w, init)).suggestName(s"${name}_${i}") } - syncv.last.io.d := io.d - syncv.last.io.en := Bool(true) + chain.last.io.d := io.d + chain.last.io.en := Bool(true) - (syncv.init zip syncv.tail).foreach { case (sink, source) => + (chain.init zip chain.tail).foreach { case (sink, source) => sink.io.d := source.io.q sink.io.en := Bool(true) } - io.q := syncv.head.io.q + io.q := chain.head.io.q + +} + +object AsyncResetShiftReg { + + def apply [T <: Chisel.Data](in: T, depth: Int = 1, init: Int = 0, name: Option[String] = None ): T = + AbstractPipelineReg(gen = {new AsyncResetShiftReg(in.getWidth, depth, init)}, in, name) +} + +//Note that it is important to ovveride "name" in order to ensure that the Chisel dedup does +// not try to merge instances of this with instances of the superclass. +class AsyncResetSynchronizerShiftReg(w: Int = 1, sync: Int = 3) extends AsyncResetShiftReg(w, depth = sync, name = "sync") { + require(sync > 0, "Sync must be greater than 0.") + override def desiredName = s"AsyncResetSynchronizerShiftReg_w${w}_d${sync}" } object AsyncResetSynchronizerShiftReg { def apply [T <: Chisel.Data](in: T, sync: Int = 3, name: Option[String] = None): T = - AbstractSynchronizerReg(gen = {new AsyncResetSynchronizerShiftReg(in.getWidth, sync)}, in, name) + AbstractPipelineReg(gen = {new AsyncResetSynchronizerShiftReg(in.getWidth, sync)}, in, name) } -class SynchronizerShiftReg(w: Int = 1, sync: Int = 3) extends AbstractSynchronizerReg(w) { +class SynchronizerShiftReg(w: Int = 1, sync: Int = 3) extends AbstractPipelineReg(w) { require(sync > 0, "Sync must be greater than 0.") override def desiredName = s"SynchronizerShiftReg_w${w}_d${sync}" @@ -84,5 +102,5 @@ class SynchronizerShiftReg(w: Int = 1, sync: Int = 3) extends AbstractSynchroniz object SynchronizerShiftReg { def apply [T <: Chisel.Data](in: T, sync: Int = 3, name: Option[String] = None): T = - AbstractSynchronizerReg(gen = { new SynchronizerShiftReg(in.getWidth, sync)}, in, name) + AbstractPipelineReg(gen = { new SynchronizerShiftReg(in.getWidth, sync)}, in, name) }