--- nand.py-
+++ nand.py
@@ -84,7 +84,10 @@
 		v = reduce(f, ivs, None)
 		for pin in self.pins:
 			if pin.conn:
-				pin.set(v)
+				if self.latency:
+					self.enque(pin.set, v)
+				else:
+					pin.set(v)
 
 	def new_pin_conn_n(self, n, targ, name, sta_i):
 		for i in range(n):
@@ -112,6 +115,14 @@
 				else:
 					targ_pin.conn = jt.new_pin()
 
+class BUF(Obj):
+	# inp, out
+	def __init__(self, parent, name='buf', latency=10):
+		# for timing
+		Obj.__init__(self, parent, name)
+		Pin(self, 'inp').conn = Joint(self, 'jt', latency).new_pin()
+		self.jt.new_pin().conn = Pin(self, 'out')
+
 class NOT(Obj):
 	# inp, out
 	def __init__(self, parent, name='not_', latency=10):
@@ -268,6 +279,16 @@
 		self.or_n.out.conn = self.not_.inp
 		self.not_.out.conn = Pin(self, 'out')
 
+class PosiNega(Obj):
+	# inp, Q, nQ
+	def __init__(self, parent, name='posi_nega', latency=10):
+		Obj.__init__(self, parent, name)
+		Pin(self, 'inp').conn = Joint(self, 'jt').new_pin()
+		BUF(self, 'buf', latency).out.conn = Pin(self, 'Q')
+		NOT(self, 'not_', latency).out.conn = Pin(self, 'nQ')
+		self.jt.new_pin().conn = self.buf.inp
+		self.jt.new_pin().conn = self.not_.inp
+
 class RSFF(Obj):
 	# R, S, Q, nQ
 	def __init__(self, parent, name='rsff', latency=10):
@@ -298,6 +319,8 @@
 		RSFF(self, 'rsff_k', latency)
 		NAND(self, 'nand_j', latency)
 		NAND(self, 'nand_k', latency)
+		BUF(self, 'buf_j', latency)
+		BUF(self, 'buf_k', latency)
 		AND(self, 'and_j', latency)
 		AND(self, 'and_k', latency)
 		Joint(self, 'jt_clk')
@@ -313,10 +336,12 @@
 		Pin(self, 'J', 'L').conn = self.nand_j.inp_b
 		Pin(self, 'K', 'L').conn = self.nand_k.inp_a
 
-		self.nand_j.out.conn = self.rsff_j.R
+		self.nand_j.out.conn = self.buf_j.inp
+		self.buf_j.out.conn = self.rsff_j.R
 		self.and_j.out.conn = self.rsff_j.S
 		self.and_k.out.conn = self.rsff_k.R
-		self.nand_k.out.conn = self.rsff_k.S
+		self.nand_k.out.conn = self.buf_k.inp
+		self.buf_k.out.conn = self.rsff_k.S
 
 		self.rsff_j.nQ.conn = self.jt_j_i.new_pin()
 		self.jt_j_i.new_pin().conn = self.rsff_o.R
@@ -350,10 +375,9 @@
 		Obj.__init__(self, parent, name)
 		JKFF(self, 'jkff', latency)
 		Pin(self, 'CLK', 'L').conn = self.jkff.CLK
-		Pin(self, 'D', 'L').conn = Joint(self, 'jt').new_pin()
-		self.jt.new_pin().conn = self.jkff.J
-		self.jt.new_pin().conn = NOT(self, 'not_', latency).inp
-		self.not_.out.conn = self.jkff.K
+		Pin(self, 'D', 'L').conn = PosiNega(self, 'posi_nega', latency).inp
+		self.posi_nega.Q.conn = self.jkff.J
+		self.posi_nega.nQ.conn = self.jkff.K
 		self.jkff.Q.conn = Pin(self, 'Q')
 		self.jkff.nQ.conn = Pin(self, 'nQ')
 
@@ -688,18 +712,18 @@
 		late = tm_from_fsec( 1.0 / ( 2 * hz ) )
 		NAND(self, 'nand', late)
 		Joint(self)
-		NOT(self, 'not_', latency)
+		PosiNega(self, 'posi_nega', latency)
 
 		Pin(self, 'en', 'L').conn = Joint(self, 'jt_en').new_pin()
 		self.jt_en.new_pin().conn = self.nand.inp_a
 		self.nand.out.conn = self.jt.new_pin()
 		self.jt.new_pin().conn = self.nand.inp_b
-		self.jt.new_pin().conn = self.not_.inp
+		self.jt.new_pin().conn = self.posi_nega.inp
 
 		GATE(self, 2, 'gate', latency)
 		self.jt_en.new_pin().conn = self.gate.en
-		self.jt.new_pin().conn = self.gate.inp_0
-		self.not_.out.conn = self.gate.inp_1
+		self.posi_nega.Q.conn = self.gate.inp_0
+		self.posi_nega.nQ.conn = self.gate.inp_1
 
 		self.gate.out_1.conn = Pin(self, 'nQ')
 		self.gate.out_0.conn = Joint(self, 'jt_out').new_pin()