diff --git a/Documentation/DALI Commands.xlsx b/Documentation/DALI Commands.xlsx
new file mode 100644
index 0000000..617d160
--- /dev/null
+++ b/Documentation/DALI Commands.xlsx
diff --git a/Documentation/Renesas DALI Applicaton Note.pdf b/Documentation/Renesas DALI Applicaton Note.pdf
new file mode 100644
index 0000000..29cbaa4
--- /dev/null
+++ b/Documentation/Renesas DALI Applicaton Note.pdf
diff --git a/Examples/Commissioning/Commissioning.ino b/Examples/Commissioning/Commissioning.ino
index 07f5ee0..fe97002 100644
--- a/Examples/Commissioning/Commissioning.ino
+++ b/Examples/Commissioning/Commissioning.ino
@@ -50,26 +50,28 @@ void loop() {
   while (Serial.available() > 0) {
     int incomingByte = Serial.read();      
     switch(incomingByte) {
-      case '1': menu_flash(); menu(); break;    
+      case '1': menu_blink(); menu(); break;    
       case '2': menu_scan_short_addr(); menu(); break;
       case '3': menu_commission(); menu(); break;
-      case '4': menu_delete_short_addr(); menu(); break;
+      case '4': menu_commission_debug(); menu(); break;
+      case '5': menu_delete_short_addr(); menu(); break;
     }
   }
 }
 
 void menu() {
   Serial.println("----------------------------");
-  Serial.println("1 Flash all lights");
+  Serial.println("1 Blink all lamps");
   Serial.println("2 Scan short addresses");
   Serial.println("3 Commission short addresses");
-  Serial.println("4 Delete short addresses");
+  Serial.println("4 Commission short addresses (VERBOSE)");
+  Serial.println("5 Delete short addresses");
   Serial.println("----------------------------");  
 }
 
 
-void menu_flash() {
-  Serial.println("Running: Flash all");
+void menu_blink() {
+  Serial.println("Running: Blinking all lamps");
   for(uint8_t i=0;i<5;i++) {
     dali.set_level(254);
     Serial.print(".");
@@ -117,8 +119,18 @@ void menu_scan_short_addr() {
 
 //might need a couple of calls to find everything...
 void menu_commission(){
-  Serial.println("Running: Commission - be patient, this takes a while ....");
-//  uint8_t cnt = dali.commission(0xff); //init_arg=0b11111111 : all without short address  
+  Serial.println("Running: Commission");
+  Serial.println("Might need a couple of runs to find all lamps ...");
+  Serial.println("Be patient, this takes a while ...");
+  uint8_t cnt = dali.commission(0xff); //init_arg=0b11111111 : all without short address  
+  Serial.print("DONE, assigned ");Serial.print(cnt);Serial.println(" new short addresses");
+}
+
+//might need a couple of calls to find everything...
+void menu_commission_debug(){
+  Serial.println("Running: Commission (VERBOSE)");
+  Serial.println("Might need a couple of runs to find all lamps ...");
+  Serial.println("Be patient, this takes a while ...");
   uint8_t cnt = debug_commission(0xff); //init_arg=0b11111111 : all without short address  
   Serial.print("DONE, assigned ");Serial.print(cnt);Serial.println(" new short addresses");
 }
@@ -140,26 +152,25 @@ uint8_t debug_commission(uint8_t init_arg) {
   uint8_t arr[64];
   uint8_t sa;
   for(sa=0; sa<64; sa++) arr[sa]=0;
-  
-  //find existing short addresses when not assigning all
-  if(init_arg!=0b00000000) {
-    Serial.println("Find existing short adr");
-    for(sa = 0; sa<64; sa++) {
-      int16_t rv = dali.cmd(DALI_QUERY_STATUS,sa);
-      if(rv!=DALI_RESULT_NO_REPLY) {
-        arr[sa]=1;
-        Serial.print("sortadr=");
-        Serial.print(sa);
-        Serial.print(" status=0x");
-        Serial.print(rv,HEX);
-        Serial.print(" minLevel=");
-        Serial.println(dali.cmd(DALI_QUERY_MIN_LEVEL,sa));
-      }
-    }
-  }
 
+  dali.cmd(DALI_RESET,0x00);
   dali.cmd(DALI_INITIALISE,init_arg);
   dali.cmd(DALI_RANDOMISE,0x00);
+  
+  //find used short addresses (run always, seems to work better than without...)
+  Serial.println("Find existing short adr");
+  for(sa = 0; sa<64; sa++) {
+    int16_t rv = dali.cmd(DALI_QUERY_STATUS,sa);
+    if(rv!=DALI_RESULT_NO_REPLY) {
+      if(init_arg!=0b00000000) arr[sa]=1; //remove address from list if not in "all" mode
+      Serial.print("sortadr=");
+      Serial.print(sa);
+      Serial.print(" status=0x");
+      Serial.print(rv,HEX);
+      Serial.print(" minLevel=");
+      Serial.println(dali.cmd(DALI_QUERY_MIN_LEVEL,sa));
+    }
+  }
 
   Serial.println("Find random adr");
   while(1) {
diff --git a/Examples/Monitor/Monitor.ino b/Examples/Monitor/Monitor.ino
new file mode 100644
index 0000000..56df038
--- /dev/null
+++ b/Examples/Monitor/Monitor.ino
@@ -0,0 +1,77 @@
+/*###########################################################################
+DALI Interface Demo
+
+Monitors all messages on the DALI bus
+
+----------------------------------------------------------------------------
+Changelog:
+2020-11-10 Created & tested on ATMega328 @ 8Mhz
+----------------------------------------------------------------------------
+		Monitor.ino - copyright qqqlab.com / github.com/qqqlab
+		
+        This program is free software: you can redistribute it and/or modify
+        it under the terms of the GNU General Public License as published by
+        the Free Software Foundation, either version 3 of the License, or
+        (at your option) any later version.
+
+        This program is distributed in the hope that it will be useful,
+        but WITHOUT ANY WARRANTY; without even the implied warranty of
+        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+        GNU General Public License for more details.
+
+        You should have received a copy of the GNU General Public License
+        along with this program.  If not, see <http://www.gnu.org/licenses/>.
+###########################################################################*/
+
+#define DALI_OUTPUT_PIN 3
+#define DALI_INPUT_PIN 4
+
+#include "qqqDali_ATMega328.h"
+
+Dali_ATMega328 dali; 
+
+uint8_t rx_out=0;
+volatile uint8_t rx_in=0;
+uint8_t rx_data[256];
+
+//callback to handle received data on dali2 interface - executes in interrupt context, store data in buffer and display in loop()
+void dali_receiver(Dali *d, uint8_t *data, uint8_t len) {
+  //push data in buffer
+  int16_t freebuf = (int16_t)256 + rx_in - rx_out - len - 2;
+  if(freebuf<=1) return; //buffer full
+  uint8_t j = rx_in;
+  rx_data[j++] = len; //push length
+  for(uint8_t i=0;i<len;i++) rx_data[j++]=data[i]; //push data
+  rx_in = j; //increment in pointer upon completion
+}
+
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("DALI Monitor Demo");
+  
+  //start the DALI interfaces
+  //arguments: tx_pin, rx_pin (negative values disable transmitter / receiver)
+  //Note: the receiver pins should be on different PCINT groups, e.g one 
+  //receiver on pin0-7 (PCINT2) one on pin8-13 (PCINT0) and one on pin14-19 (PCINT1)
+  dali.begin(DALI_OUTPUT_PIN, DALI_INPUT_PIN); 
+
+  //attach a received data handler
+  dali.EventHandlerReceivedData = dali_receiver;  
+}
+
+#define MIN_LEVEL 100   //most LED Drivers do not get much lower than this
+int16_t level = 254;    //254 is max level, 1 is min level (if driver supports it), 0 is off
+int8_t level_step = 4;
+
+void loop() {  
+  if(rx_out!=rx_in) {
+    //Serial.print("RX:");
+    uint8_t len = rx_data[rx_out++];   
+    for(uint8_t i=0;i<len;i++) {
+      Serial.print(rx_data[rx_out++],HEX);
+      Serial.print(' ');
+    }
+    Serial.println();
+  }
+}
diff --git a/qqqDali.cpp b/qqqDali.cpp
index 73cca33..1b35ff3 100644
--- a/qqqDali.cpp
+++ b/qqqDali.cpp
@@ -24,7 +24,7 @@ Changelog:
 //###########################################################################
 // Helpers
 //###########################################################################
-#define DALI_TOL 15 //allow for 15% tolerance on timing (DALI spec calls for 10%, add 5% for uc clock tolerance)
+#define DALI_TOL 25 //percentage tolerance on timing. DALI specs call for 10%, but use higher value to allow for implementation micros() jitter. NOTE: Max value is 50% to differentiate between TE and 2TE.
 #define DALI_TE ((1000000+(DALI_BAUD))/(2*(DALI_BAUD)))  //417us
 #define DALI_TE_MIN ((100-DALI_TOL)*DALI_TE)/100 
 #define DALI_TE_MAX ((100+DALI_TOL)*DALI_TE)/100 
@@ -157,7 +157,7 @@ void Dali::ISR_pinchange() {
       this->rx_state = RX_IDLE;
       //TODO rx error
       return;
-    }		
+    }
     break;
   }
 }
@@ -177,34 +177,42 @@ void Dali::push_halfbit(uint8_t bit) {
 //###########################################################################
 // Dali Class
 //###########################################################################
+
+//non blocking send - check tx_state for completion, check tx_collision for collision errors
 uint8_t Dali::send(uint8_t* tx_msg, uint8_t tx_len_bytes) {
-  if(tx_len_bytes>3) return -(DALI_RESULT_INVALID_TOO_LONG);
+  if(tx_len_bytes>3) return -(DALI_RESULT_DATA_TOO_LONG);
   if(this->tx_state != TX_IDLE) return -(DALI_RESULT_TIMEOUT); 
   for(uint8_t i=0;i<tx_len_bytes;i++) this->tx_msg[i]=tx_msg[i];
   this->tx_len = tx_len_bytes<<3;
   this->tx_collision=0;
-  this->tx_state = TX_START;
+  this->tx_state = TX_START; //start transmission
   return 0;
 }
 
+//blocking send - wait until successful send or timeout
 uint8_t Dali::sendwait(uint8_t* tx_msg, uint8_t tx_len_bytes, uint32_t timeout_us) {
-  if(tx_len_bytes>3) return -(DALI_RESULT_INVALID_TOO_LONG);
+  if(tx_len_bytes>3) return -(DALI_RESULT_DATA_TOO_LONG);
   uint32_t ts = HAL_micros();
-  //wait for idle
-  while(this->tx_state != TX_IDLE) {
-    if(HAL_micros() - ts > timeout_us) return -(DALI_RESULT_TIMEOUT); 
-  }
-  //start transmit
-  uint8_t rv = this->send(tx_msg,tx_len_bytes);
-  if(rv) return rv;
-  //wait for completion
-  while(this->tx_state != TX_IDLE) {
-    if(HAL_micros() - ts > timeout_us) return -(DALI_RESULT_TX_TIMEOUT); 
+  
+  while(1) {
+    //wait for idle
+    while(this->tx_state != TX_IDLE) {
+      if(HAL_micros() - ts > timeout_us) return -(DALI_RESULT_TIMEOUT); 
+    }
+    //start transmit
+    uint8_t rv = this->send(tx_msg,tx_len_bytes);
+    if(rv) return rv;
+    //wait for completion
+    while(this->tx_state != TX_IDLE) {
+      if(HAL_micros() - ts > timeout_us) return -(DALI_RESULT_TX_TIMEOUT); 
+    }
+    //check for collisions
+    if(this->tx_collision==0) return 0;
   }
-  return 0;
+  return -(DALI_RESULT_TIMEOUT);
 }
 
-//transmit 2 byte command, receive 1 byte reply
+//blocking transmit 2 byte command, receive 1 byte reply (if reply was sent)
 int16_t Dali::tx(uint8_t cmd0, uint8_t cmd1, uint32_t timeout_us) {
   uint8_t tx[2];
   tx[0] = cmd0; 
@@ -227,8 +235,6 @@ int16_t Dali::tx(uint8_t cmd0, uint8_t cmd1, uint32_t timeout_us) {
   return this->rx_msg[0];
 }
 
-
-
 //=================================================================
 // High level
 //=================================================================
@@ -324,7 +330,7 @@ void Dali::set_searchaddr(uint32_t adr) {
   this->cmd(DALI_SEARCHADDRL,adr);
 }
 
-//set search address, but set only changed bytes
+//set search address, but set only changed bytes (takes less time)
 void Dali::set_searchaddr_diff(uint32_t adr_new,uint32_t adr_current) {
   if( (uint8_t)(adr_new>>16) !=  (uint8_t)(adr_current>>16) ) this->cmd(DALI_SEARCHADDRH,adr_new>>16);
   if( (uint8_t)(adr_new>>8)  !=  (uint8_t)(adr_current>>8)  ) this->cmd(DALI_SEARCHADDRM,adr_new>>8);
@@ -336,8 +342,6 @@ uint8_t Dali::compare() {
   return (0xff == this->cmd(DALI_COMPARE,0x00));
 }
 
-
-
 //The slave shall store the received 6-bit address (AAAAAA) as a short address if it is selected.
 void Dali::program_short_address(uint8_t shortadr) {
   this->cmd(DALI_PROGRAM_SHORT_ADDRESS, (shortadr << 1) | 0x01);
@@ -384,57 +388,45 @@ uint8_t Dali::commission(uint8_t init_arg) {
   uint8_t arr[64];
   uint8_t sa;
   for(sa=0; sa<64; sa++) arr[sa]=0;
-  
-  //find existing short addresses when not assigning all
-  if(init_arg!=0b00000000) {
-    //Serial.println("Short adr");
-    for(sa = 0; sa<64; sa++) {
-      int16_t rv = this->cmd(DALI_QUERY_STATUS,sa);
-      if(rv!=DALI_RESULT_NO_REPLY) {
-        arr[sa]=1;
-        //Serial.print(sa);
-        //Serial.print(" status=0x");
-        //Serial.print(rv,HEX);
-        //Serial.print(" minLevel=");
-        //Serial.println(this->cmd(DALI_QUERY_MIN_LEVEL,sa));
-      }
-    }
-  }
 
+  //start commissioning
+  this->cmd(DALI_RESET,0x00);
   this->cmd(DALI_INITIALISE,init_arg);
   this->cmd(DALI_RANDOMISE,0x00);
+  
+  //find used short addresses (run always, seems to work better than without...)
+  for(sa = 0; sa<64; sa++) {
+    int16_t rv = this->cmd(DALI_QUERY_STATUS,sa);
+    if(rv!=DALI_RESULT_NO_REPLY) {
+      if(init_arg!=0b00000000) arr[sa]=1; //remove address from list if not in "all" mode
+    }
+  }
 
+  //find random addresses and assign unused short addresses
   while(1) {
-    //Serial.print("addr=");
-    //Serial.println(this->get_random_address(0xff),HEX);
-
     uint32_t adr = this->find_addr();
     if(adr>0xffffff) break; //no more random addresses found -> exit
-    //Serial.print("found adr=");
-    //Serial.println(adr,HEX);
 
-    //Serial.print("short adr=");
-    //Serial.println(dali_query_short_address());
-  
-    //find available address
+    //find first unused short address
     for(sa=0; sa<64; sa++) {
       if(arr[sa]==0) break;
     }
     if(sa>=64) break; //all 64 short addresses assigned -> exit
+
+    //mark short address as used
     arr[sa] = 1;
     cnt++;
  
-    //Serial.print("program short adr=");
-    //Serial.println(sa);
+    //assign short address
     this->program_short_address(sa);
-    //dali_program_short_address(0xff);
-  
-    //Serial.print("read short adr=");
+
     //Serial.println(this->query_short_address()); //TODO check read adr, handle if not the same...
 
+    //remove the device from the search
     this->cmd(DALI_WITHDRAW,0x00);
   }
-  
+
+  //terminate the DALI_INITIALISE command
   this->cmd(DALI_TERMINATE,0x00);
   return cnt;
 }
diff --git a/qqqDali.h b/qqqDali.h
index 3cfdc96..ee3efd6 100644
--- a/qqqDali.h
+++ b/qqqDali.h
@@ -60,7 +60,7 @@ public:
 
   //initialize variables
   Dali() : tx_state(TX_IDLE), rx_state(RX_IDLE), tx_bus_low(0), tx_len(0), EventHandlerReceivedData(0) {};
-  
+
 protected:
   //low level functions
   enum tx_stateEnum { TX_IDLE=0,TX_START,TX_START_X,TX_BIT,TX_BIT_X,TX_STOP1,TX_STOP1_X,TX_STOP2,TX_STOP2_X,TX_STOP3};
@@ -79,6 +79,8 @@ protected:
   volatile uint8_t rx_len; //number of bytes received
   volatile int8_t rx_halfbitlen; //number of half bits received
   volatile uint8_t rx_last_halfbit; //last halfbit received
+  
+
 
   volatile uint8_t bus_idle_te_cnt; //number of Te since start of idle bus
 
@@ -94,13 +96,12 @@ protected:
 
 #define DALI_BAUD 1200
 
-#define DALI_RESULT_TIMEOUT -1 //Timeout waiting for DALI bus
-#define DALI_RESULT_INVALID_TOO_LONG -2 //Trying to send too many bytes (max 3)
-#define DALI_RESULT_TX_TIMEOUT -3 //Timeout during transmission
-#define DALI_RESULT_NO_REPLY -4 //cmd() did not receive a reply (i.e. received a 'NO' Backward Frame)
-#define DALI_RESULT_INVALID_CMD -5 //The cmd argument in the call to cmd() was invalid
-#define DALI_RESULT_INVALID_REPLY -6 //cmd() received an invalid reply (too long)
-
+#define DALI_RESULT_TIMEOUT          -1 //Timeout waiting for DALI bus
+#define DALI_RESULT_DATA_TOO_LONG    -2 //Trying to send too many bytes (max 3)
+#define DALI_RESULT_TX_TIMEOUT       -3 //Timeout during transmission
+#define DALI_RESULT_NO_REPLY         -4 //cmd() did not receive a reply (i.e. received a 'NO' Backward Frame)
+#define DALI_RESULT_INVALID_CMD      -5 //The cmd argument in the call to cmd() was invalid
+#define DALI_RESULT_INVALID_REPLY    -6 //cmd() received an invalid reply (too long)
 
 //bit8=extended commands, bit9=repeat
 #define DALI_OFF 0 //0  - Turns off lighting.