diff --git a/tb/asmicon/common.py b/tb/asmicon/common.py
new file mode 100644
index 000000000..f5ff89643
--- /dev/null
+++ b/tb/asmicon/common.py
@@ -0,0 +1,41 @@
+from migen.fhdl.structure import *
+from migen.sim.generic import Proxy
+
+class CommandLogger:
+	def __init__(self, cmd):
+		self.cmd = cmd
+	
+	def do_simulation(self, s):
+		elts = ["@" + str(s.cycle_counter)]
+		
+		cmdp = Proxy(s, self.cmd)
+		if not cmdp.ras_n and cmdp.cas_n and cmdp.we_n:
+			elts.append("ACTIVATE")
+			elts.append("BANK " + str(cmdp.ba))
+			elts.append("ROW " + str(cmdp.a))
+		elif cmdp.ras_n and not cmdp.cas_n and cmdp.we_n:
+			elts.append("READ\t")
+			elts.append("BANK " + str(cmdp.ba))
+			elts.append("COL " + str(cmdp.a))
+		elif cmdp.ras_n and not cmdp.cas_n and not cmdp.we_n:
+			elts.append("WRITE\t")
+			elts.append("BANK " + str(cmdp.ba))
+			elts.append("COL " + str(cmdp.a))
+		elif cmdp.ras_n and cmdp.cas_n and not cmdp.we_n:
+			elts.append("BST")
+		elif not cmdp.ras_n and not cmdp.cas_n and cmdp.we_n:
+			elts.append("AUTO REFRESH")
+		elif not cmdp.ras_n and cmdp.cas_n and not cmdp.we_n:
+			elts.append("PRECHARGE")
+			if cmdp.a & 2**10:
+				elts.append("ALL")
+			else:
+				elts.append("BANK " + str(cmdp.ba))
+		elif not cmdp.ras_n and not cmdp.cas_n and not cmdp.we_n:
+			elts.append("LMR")
+		
+		if len(elts) > 1:
+			print("\t".join(elts))
+	
+	def get_fragment(self):
+		return Fragment(sim=[self.do_simulation])
diff --git a/tb/asmicon/refresher.py b/tb/asmicon/refresher.py
new file mode 100644
index 000000000..cbf1d47e7
--- /dev/null
+++ b/tb/asmicon/refresher.py
@@ -0,0 +1,50 @@
+from random import Random
+
+from migen.fhdl.structure import *
+from migen.sim.generic import Simulator, TopLevel
+from migen.sim.icarus import Runner
+
+from milkymist.asmicon.refresher import *
+
+from common import CommandLogger
+
+class Granter:
+	def __init__(self, req, ack):
+		self.req = req
+		self.ack = ack
+		self.state = 0
+		self.prng = Random(92837)
+	
+	def do_simulation(self, s):
+		elts = ["@" + str(s.cycle_counter)]
+		
+		if self.state == 0:
+			if s.rd(self.req):
+				elts.append("Refresher requested access")
+				self.state = 1
+		elif self.state == 1:
+			if self.prng.randrange(0, 5) == 0:
+				elts.append("Granted access to refresher")
+				s.wr(self.ack, 1)
+				self.state = 2
+		elif self.state == 2:
+			if not s.rd(self.req):
+				elts.append("Refresher released access")
+				s.wr(self.ack, 0)
+				self.state = 0
+			
+		if len(elts) > 1:
+			print("\t".join(elts))
+	
+	def get_fragment(self):
+		return Fragment(sim=[self.do_simulation])
+
+def main():
+	dut = Refresher(13, 2, tRP=3, tREFI=100, tRFC=5)
+	logger = CommandLogger(dut.cmd)
+	granter = Granter(dut.req, dut.ack)
+	fragment = dut.get_fragment() + logger.get_fragment() + granter.get_fragment()
+	sim = Simulator(fragment, Runner())
+	sim.run(400)
+
+main()