micropython
diff --git a/‎extmod/uasyncio/core.py‎
Lines changed: 6 additions & 5 deletions b/‎extmod/uasyncio/core.py‎
Lines changed: 6 additions & 5 deletions
@@ -29,15 +29,16 @@ class TimeoutError(Exception):
 # "Yield" once, then raise StopIteration
 class SingletonGenerator:
     def __init__(self):
-        self.state = 0
+        self.state = None
         self.exc = StopIteration()
 
     def __iter__(self):
         return self
 
     def __next__(self):
-        if self.state:
-            self.state = 0
+        if self.state is not None:
+            _task_queue.push_sorted(cur_task, self.state)
+            self.state = None
             return None
         else:
             self.exc.__traceback__ = None
@@ -47,8 +48,8 @@ def __next__(self):
 # Pause task execution for the given time (integer in milliseconds, uPy extension)
 # Use a SingletonGenerator to do it without allocating on the heap
 def sleep_ms(t, sgen=SingletonGenerator()):
-    _task_queue.push_sorted(cur_task, ticks_add(ticks(), t))
-    sgen.state = 1
+    assert sgen.state is None
+    sgen.state = ticks_add(ticks(), t)
     return sgen