diff --git a/se/sics/mspsim/chip/CC2420.java b/se/sics/mspsim/chip/CC2420.java
index a4dc418..2c4299a 100644
--- a/se/sics/mspsim/chip/CC2420.java
+++ b/se/sics/mspsim/chip/CC2420.java
@@ -661,6 +661,7 @@ public class CC2420 extends Chip implements USARTListener, RFListener, RFSource
   }
 
   private void setReg(int address, int data) {
+      int oldValue = registers[address];
       registers[address] = data;
       switch(address) {
       case REG_IOCFG0:
@@ -682,12 +683,13 @@ public class CC2420 extends Chip implements USARTListener, RFListener, RFSource
           autoAck = (data & AUTOACK) != 0;
           break;
       case REG_FSCTRL:
-      	if (cl != null) {
-      		updateActiveFrequency();
-      		cl.changedChannel(activeChannel);
-      	}
+          if (cl != null) {
+              updateActiveFrequency();
+              cl.changedChannel(activeChannel);
+          }
         break;
       }
+      configurationChanged(address, oldValue, data);
   }
     
   public void dataReceived(USART source, int data) {
diff --git a/se/sics/mspsim/core/Chip.java b/se/sics/mspsim/core/Chip.java
index 1e265ee..ab65151 100644
--- a/se/sics/mspsim/core/Chip.java
+++ b/se/sics/mspsim/core/Chip.java
@@ -181,7 +181,7 @@ public abstract class Chip implements Loggable, EventSource {
   /* Called by subclasses to inform about changes of configuration */
   protected void configurationChanged(int parameter, int oldValue, int newValue) {
       ConfigurationChangeListener[] listeners = ccListeners;
-      if (listeners != null) {
+      if (oldValue != newValue && listeners != null) {
           for (int i = 0, n = listeners.length; i < n; i++) {
               listeners[i].configurationChanged(this, parameter, oldValue, newValue);
           }