add assert on ControlBase.connect, stage should be None

diff --git a/src/add/singlepipe.py b/src/add/singlepipe.py
index 7d08ccff4f0ed6e7023336cc9e44b4fc3eca4f21..d62c9395e7ad883369d7596cfdf59e012aa922d1 100644 (file)
--- a/src/add/singlepipe.py
+++ b/src/add/singlepipe.py
@@ -1,11 +1,10 @@
-""" Pipeline and BufferedHandshake implementation, conforming to the same API.
-    For multi-input and multi-output variants, see multipipe.
+""" Pipeline API.  For multi-input and multi-output variants, see multipipe.
 
     Associated development bugs:
     * http://bugs.libre-riscv.org/show_bug.cgi?id=64
     * http://bugs.libre-riscv.org/show_bug.cgi?id=57
 
-    Important: see Stage API (iocontrol.py) in combination with below
+    Important: see Stage API (stageapi.py) in combination with below
 
     RecordBasedStage:
     ----------------
@@ -270,6 +269,7 @@ class ControlBase(StageHelper, Elaboratable):
               an elaborate() to m.d.comb
         """
         assert len(pipechain) > 0, "pipechain must be non-zero length"
+        assert self.stage is None, "do not use connect with a stage"
         eqs = [] # collated list of assignment statements
 
         # connect inter-chain