diff --git a/stubs/amaranth/sim/core.pyi b/stubs/amaranth/sim/core.pyi
index 23fef3472..58241c6bb 100644
--- a/stubs/amaranth/sim/core.pyi
+++ b/stubs/amaranth/sim/core.pyi
@@ -5,6 +5,7 @@ This type stub file was generated by pyright.
 from .._utils import deprecated
 from ..hdl.cd import *
 from ..hdl.ir import *
+from .pysim import *
 
 __all__ = ["Settle", "Delay", "Tick", "Passive", "Active", "Simulator"]
 class Command:
@@ -48,6 +49,9 @@ class Active(Command):
 
 
 class Simulator:
+    _fragment : Fragment
+    _engine : PySimEngine
+    _clocked  : set
     def __init__(self, fragment, *, engine=...) -> None:
         ...
     
diff --git a/test/common/_test/test_infrastructure.py b/test/common/_test/test_infrastructure.py
index ecf1c84d9..5dea7ba67 100644
--- a/test/common/_test/test_infrastructure.py
+++ b/test/common/_test/test_infrastructure.py
@@ -29,3 +29,30 @@ def process(self):
     def test_random(self):
         with self.run_simulation(self.m, 50) as sim:
             sim.add_sync_process(self.process)
+
+
+class TestTrueSettle(TestCaseWithSimulator):
+    def setUp(self):
+        self.m = SimpleTestCircuit(EmptyCircuit())
+        self.test_cycles = 10
+        self.flag = False
+        random.seed(14)
+
+    def true_settle_process(self):
+        for k in range(self.test_cycles):
+            yield TrueSettle()
+            self.assertTrue(self.flag)
+            self.flag = False
+            yield
+
+    def flag_process(self):
+        for k in range(self.test_cycles):
+            for i in range(random.randrange(0, 5)):
+                yield Settle()
+            self.flag = True
+            yield
+
+    def test_flag(self):
+        with self.run_simulation(self.m, 50) as sim:
+            sim.add_sync_process(self.true_settle_process)
+            sim.add_sync_process(self.flag_process)
diff --git a/test/common/infrastructure.py b/test/common/infrastructure.py
index 058d5b9ed..4c6106c92 100644
--- a/test/common/infrastructure.py
+++ b/test/common/infrastructure.py
@@ -2,6 +2,7 @@
 import random
 import unittest
 import functools
+from enum import Enum
 from contextlib import contextmanager, nullcontext
 from typing import TypeVar, Generic, Type, TypeGuard, Any, Union, Callable, cast, TypeAlias
 from abc import ABC
@@ -109,14 +110,32 @@ class Now(CoreblocksCommand):
     pass
 
 
+class TrueSettle(CoreblocksCommand):
+    """Wait till all process are waiting for the next cycle or for the TrueSettle"""
+
+    pass
+
+
+class SyncProcessState(Enum):
+    """State of SyncProcessWrapper."""
+
+    sleeping = 0  # Wait for the next cycle
+    running = 1
+    ended = 2
+    true_settle = 3  # Wait for the TrueSettle
+
+
 class SyncProcessWrapper:
     def __init__(self, f):
         self.org_process = f
         self.current_cycle = 0
+        self.state = None
+        self.blocked = None
 
     def _wrapping_function(self):
         response = None
         org_coroutine = self.org_process()
+        self.state = SyncProcessState.running
         try:
             while True:
                 # call orginal test process and catch data yielded by it in `command` variable
@@ -124,14 +143,26 @@ def _wrapping_function(self):
                 # If process wait for new cycle
                 if command is None:
                     self.current_cycle += 1
+                    self.state = SyncProcessState.sleeping
                     # forward to amaranth
                     yield
-                elif isinstance(command, Now):
-                    response = self.current_cycle
+                    self.state = SyncProcessState.running
+                elif isinstance(command, CoreblocksCommand):
+                    if isinstance(command, Now):
+                        response = self.current_cycle
+                    elif isinstance(command, TrueSettle):
+                        self.state = SyncProcessState.true_settle
+                        self.blocked = True
+                        while self.blocked:
+                            yield Settle()
+                        self.state = SyncProcessState.running
+                    else:
+                        raise RuntimeError(f"Not known CoreblocksCommand: {command}")
                 # Pass everything else to amaranth simulator without modifications
                 else:
                     response = yield command
         except StopIteration:
+            self.state = SyncProcessState.ended
             pass
 
 
@@ -168,15 +199,30 @@ def __init__(self, module: HasElaborate, max_cycles: float = 10e4, add_transacti
             self.ctx = nullcontext()
 
         self.deadline = clk_period * max_cycles
+        self.sync_proc_list = []
 
     def add_sync_process(self, f: Callable[[], TestGen]):
         f_wrapped = SyncProcessWrapper(f)
+        self.sync_proc_list.append(f_wrapped)
         super().add_sync_process(f_wrapped._wrapping_function)
 
-    def run(self) -> bool:
-        with self.ctx:
-            self.run_until(self.deadline)
+    def _check_true_settle_ready(self):
+        return all(p.state != SyncProcessState.running for p in self.sync_proc_list)
 
+    def _unblock_sync_processes(self):
+        for p in self.sync_proc_list:
+            if p.blocked:
+                p.blocked = False
+
+    def run(self) -> bool:
+        deadline = self.deadline * 1e12
+        assert self._engine.now <= deadline
+        last_now = self._engine.now
+        while self.advance() and self._engine.now < deadline:
+            if last_now == self._engine.now:
+                if self._check_true_settle_ready():
+                    self._unblock_sync_processes()
+            last_now = self._engine.now
         return not self.advance()