diff --git a/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp b/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp
index 8c43971..20a12af 100644
--- a/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp
+++ b/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp
@@ -188,8 +188,8 @@ void SpinCorePulseBlaster::run_pulse_program_w_sync(state& exp, double sync_freq
         // reported to SpinCore  (Contact Request 2016-12-19 at 1482143561)
         // markusro: When is this necessary? (TODO)
 	    c=prog->create_command();
-	    //c->ttls=sync_mask;
-	    c->ttls = 0x0;
+	    c->ttls=sync_mask;
+	    //c->ttls = 0x0;
 	    c->instruction=SpinCorePulseBlaster::CONTINUE;
 	    //c->length=shortest_pulse+2; //
 	    c->length=12; // markusro: why shortest_pulse+2=11  , tests show 120 ns minimum state time??
@@ -204,7 +204,7 @@ void SpinCorePulseBlaster::run_pulse_program_w_sync(state& exp, double sync_freq
           PulseBlasterCommand* c;
           c=prog->create_command();
           c->instruction=SpinCorePulseBlaster::CONTINUE;
-          c->length=shortest_pulse+2;
+          c->length=shortest_pulse+3;
           prog->push_front(c);
           duration+=(1.0+shortest_pulse)/clock;
   }