diff --git a/src/main/scala/junctions/crossing.scala b/src/main/scala/junctions/crossing.scala
index c68f5e2a..4a17fde7 100644
--- a/src/main/scala/junctions/crossing.scala
+++ b/src/main/scala/junctions/crossing.scala
@@ -85,43 +85,3 @@ object AsyncIrrevocableFrom
     PostQueueIrrevocablize(AsyncDecoupledFrom(from_clock, from_reset, from_source, depth, sync))
   }
 }
-
-/**  Because Chisel/FIRRTL does not allow us
-  *  to directly assign clocks from Signals,
-  *  we need this black box module.
-  *  This may even be useful because some back-end
-  *  flows like to have this sort of transition
-  *  flagged with a special cell or module anyway.
-  */
-
-class SignalToClock extends BlackBox {
-  val io = new Bundle {
-    val signal_in = Bool(INPUT)
-    val clock_out = Clock(OUTPUT)
-  }
-
-  //  io.clock_out := io.signal_in
-}
-
-object SignalToClock {
-  def apply(signal: Bool): Clock = {
-    val s2c = Module(new SignalToClock)
-    s2c.io.signal_in := signal
-    s2c.io.clock_out
-  }
-}
-
-class ClockToSignal extends BlackBox {
-  val io = new Bundle {
-    val clock_in = Clock(INPUT)
-    val signal_out = Bool(OUTPUT)
-  }
-}
-
-object ClockToSignal {
-  def apply(clk: Clock): Bool = {
-    val c2s = Module(new ClockToSignal)
-    c2s.io.clock_in := clk
-    c2s.io.signal_out
-  }
-}
diff --git a/vsim/Makefrag b/vsim/Makefrag
index 36606737..8d694ea6 100644
--- a/vsim/Makefrag
+++ b/vsim/Makefrag
@@ -10,8 +10,6 @@ bb_vsrcs = $(base_dir)/vsrc/DebugTransportModuleJtag.v \
 	$(base_dir)/vsrc/AsyncResetReg.v \
 	$(base_dir)/vsrc/AsyncSetReg.v \
 	$(base_dir)/vsrc/ClockDivider.v \
-	$(base_dir)/vsrc/ClockToSignal.v \
-	$(base_dir)/vsrc/SignalToClock.v \
 
 
 sim_vsrcs = \
diff --git a/vsrc/ClockToSignal.v b/vsrc/ClockToSignal.v
deleted file mode 100644
index db8b8b37..00000000
--- a/vsrc/ClockToSignal.v
+++ /dev/null
@@ -1,19 +0,0 @@
-  
-/* This blackbox is needed by 
- * Chisel in order to do type conversion.
- * It may be useful for some synthesis flows
- * as well which require special 
- * flagging on conversion from data to clock.
- */
-
-
-module ClockToSignal(
-             output signal_out,
-             input  clock_in
-                      );
-   
-
-  assign signal_out = clock_in;
-                       
-endmodule // ClockToSignal
-
diff --git a/vsrc/SignalToClock.v b/vsrc/SignalToClock.v
deleted file mode 100644
index 553bc580..00000000
--- a/vsrc/SignalToClock.v
+++ /dev/null
@@ -1,18 +0,0 @@
-  
-/* This blackbox is needed by 
- * Chisel in order to do type conversion.
- * It may be useful for some synthesis flows
- * as well which require special 
- * flagging on conversion from data to clock.
- */
-
-
-module SignalToClock (
-             output clock_out,
-             input  signal_in
-                      );
-   
-
-  assign clock_out = signal_in;
-                       
-endmodule // SignalToClock