diff --git a/firmware/command_ctrl.ino b/firmware/command_ctrl.ino
index 746b557..44fd39c 100644
--- a/firmware/command_ctrl.ino
+++ b/firmware/command_ctrl.ino
@@ -24,8 +24,10 @@ void cc_clearReadDataBuffer(void);
 void cc_setStartFreq(void);
 void cc_setEndFreq(void);
 void cc_setIntervall(void);
+void cc_setFreqStep(void);
 void cc_setDriveStrength(void);
 void cc_startMeasurement(void);
+void cc_getConfig(void);
 
 /*****************************************************************************/
 
@@ -40,7 +42,9 @@ uint8_t cc_commands[] = {
     CC_CMD_SET_END_FREQ,
     CC_CMD_SET_INTERVALL,
     CC_CMD_SET_DRIVE_STRENGTH,
+    CC_CMD_SET_FREQ_STEP,
     CC_CMD_START_MEASUREMENT,
+    CC_CMD_GET_CONFIG,
   };
 
 void (*cc_cmd_functions[])() = {
@@ -48,7 +52,9 @@ void (*cc_cmd_functions[])() = {
     CC_CMD_SET_END_FREQ_FUNC,
     CC_CMD_SET_INTERVALL_FUNC,
     CC_CMD_SET_DRIVE_STRENGTH_FUNC,
+    CC_CMD_SET_FREQ_STEP_FUNC,
     CC_CMD_START_MEASUREMENT_FUNC,
+    CC_CMD_GET_CONFIG_FUNC,
   };
 
 uint8_t cc_cmd_data_to_read[] = {
@@ -56,7 +62,9 @@ uint8_t cc_cmd_data_to_read[] = {
     CC_CMD_SET_END_FREQ_DATA_TO_READ,
     CC_CMD_SET_INTERVALL_DATA_TO_READ,
     CC_CMD_SET_DRIVE_STRENGTH_DATA_TO_READ,
+    CC_CMD_SET_FREQ_STEP_DATA_TO_READ,
     CC_CMD_START_MEASUREMENT_DATA_TO_READ,
+    CC_CMD_GET_CONFIG_DATA_TO_READ,
   };
 
 uint8_t cc_read_data[CC_READ_DATA_MAX];
@@ -75,47 +83,207 @@ uint8_t cc_cmd_data_read_cnt = 0;
 
 void cc_setStartFreq()
 {
+  uint32_t tmp_start_freq  = (uint32_t)cc_read_data[0] << 24;
+           tmp_start_freq += (uint32_t)cc_read_data[1] << 16;
+           tmp_start_freq += (uint32_t)cc_read_data[2] <<  8;
+           tmp_start_freq += (uint32_t)cc_read_data[3];
+  if (tmp_start_freq < 1)
+    tmp_start_freq = 1;
+  if (tmp_start_freq > 150000000)
+    tmp_start_freq = 150000000;
+
+  start_freq = tmp_start_freq;
+
   char* tmp = "     ";
   sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
-                             MSG_TYPE_ANSWER_NOK,
+                             MSG_TYPE_ANSWER_OK,
                              MSG_EOM1, MSG_EOM2);
   Serial.write(tmp);
 }
 
 void cc_setEndFreq()
 {
+  uint32_t tmp_end_freq  = (uint32_t)cc_read_data[0] << 24;
+           tmp_end_freq += (uint32_t)cc_read_data[1] << 16;
+           tmp_end_freq += (uint32_t)cc_read_data[2] <<  8;
+           tmp_end_freq += (uint32_t)cc_read_data[3];
+  if (tmp_end_freq < 1)
+    tmp_end_freq = 1;
+  if (tmp_end_freq > 150000000)
+    tmp_end_freq = 150000000;
+
+  end_freq = tmp_end_freq;
+
   char* tmp = "     ";
   sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
-                             MSG_TYPE_ANSWER_NOK,
+                             MSG_TYPE_ANSWER_OK,
+                             MSG_EOM1, MSG_EOM2);
+  Serial.write(tmp);
+}
+
+void cc_setFreqStep()
+{
+  uint32_t tmp_step_freq  = (uint32_t)cc_read_data[0] << 24;
+           tmp_step_freq += (uint32_t)cc_read_data[1] << 16;
+           tmp_step_freq += (uint32_t)cc_read_data[2] <<  8;
+           tmp_step_freq += (uint32_t)cc_read_data[3];
+  if (tmp_step_freq < 1)
+    tmp_step_freq = 1;
+  if (tmp_step_freq > 150000000)
+    tmp_step_freq = 150000000;
+
+  step_freq = tmp_step_freq;
+
+  char* tmp = "     ";
+  sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
+                             MSG_TYPE_ANSWER_OK,
                              MSG_EOM1, MSG_EOM2);
   Serial.write(tmp);
 }
 
 void cc_setIntervall()
 {
+  uint16_t tmp_intervall  = (uint16_t)cc_read_data[0] << 8;
+           tmp_intervall += (uint16_t)cc_read_data[1];
+  if (tmp_intervall < 1)
+    tmp_intervall = 1;
+  if (tmp_intervall > 150000000)
+    tmp_intervall = 150000000;
+
+  intervall = tmp_intervall;
+
   char* tmp = "     ";
   sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
-                             MSG_TYPE_ANSWER_NOK,
+                             MSG_TYPE_ANSWER_OK,
                              MSG_EOM1, MSG_EOM2);
   Serial.write(tmp);
 }
 
 void cc_setDriveStrength()
 {
-  char* tmp = "     ";
-  sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
-                             MSG_TYPE_ANSWER_NOK,
-                             MSG_EOM1, MSG_EOM2);
-  Serial.write(tmp);
+  enum si5351_drive tmp_ds  = (enum si5351_drive)cc_read_data[0];
+  if (tmp_ds == SI5351_DRIVE_2MA ||
+      tmp_ds == SI5351_DRIVE_4MA ||
+      tmp_ds == SI5351_DRIVE_6MA ||
+      tmp_ds == SI5351_DRIVE_8MA)
+  {
+    drive_str = tmp_ds;
+
+    char* tmp = "     ";
+    sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
+                               MSG_TYPE_ANSWER_OK,
+                               MSG_EOM1, MSG_EOM2);
+    Serial.write(tmp);
+  } else {
+
+    char* tmp = "     ";
+    sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
+                               MSG_TYPE_ANSWER_NOK,
+                               MSG_EOM1, MSG_EOM2);
+    Serial.write(tmp);
+  }
 }
 
 void cc_startMeasurement()
 {
-  char* tmp = "     ";
-  sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
-                             123,
-                             MSG_EOM1, MSG_EOM2);
-  Serial.write(tmp);
+
+  // 1. send measurement info to host
+  //    MSG_TYPE_CONFIG
+  cc_getConfig();
+
+  // 2. start a for loop from the frequence to start to the end frequence
+  if (start_freq > 0 && start_freq <= 150000000 &&
+      end_freq > 0 && end_freq <= 150000000 &&
+      start_freq < end_freq &&
+      intervall > 0 &&
+      step_freq > 0)
+  {
+    si5351.drive_strength(SI5351_CLK0, drive_str); // 2 4 6 8ma
+
+    uint32_t freq = 0;
+    for (freq = start_freq; freq < end_freq; freq += step_freq)
+    {
+      uint32_t a0_sum  = 0;
+      uint32_t a1_sum  = 0;
+      uint16_t i = 0;
+
+      si5351.set_freq(freq * 100, SI5351_PLL_FIXED, SI5351_CLK0);
+      si5351.output_enable(SI5351_CLK0, 1); // enable clock output 0
+      delay(1);
+
+      for (i = 0; i < intervall; i++)
+      {
+        // 3. on every loop read the analog input A0 and A1 for the in intervall (milliseconds)
+        //    and generate the average value, read the ADC value every milli second.
+        a0_sum += analogRead(A0);
+        a1_sum += analogRead(A1);
+
+        delay(1);
+      }
+
+      a0_sum = a0_sum / intervall;
+      a1_sum = a1_sum / intervall;
+
+      // 4. send the current output frequency, the drive strength and the measured ADC values from A0 and A1 to the host
+      //    MSG_TYPE_MEAS_FREQ_INFO
+      Serial.write(MSG_SOM1);
+      Serial.write(MSG_SOM2);
+      Serial.write(MSG_TYPE_MEAS_FREQ_INFO);
+      Serial.write((uint8_t)((freq & 0xff000000) >> 24));
+      Serial.write((uint8_t)((freq & 0x00ff0000) >> 16));
+      Serial.write((uint8_t)((freq & 0x0000ff00) >>  8));
+      Serial.write((uint8_t) (freq & 0x000000ff));
+      Serial.write((uint8_t)((a0_sum & 0xff00) >> 8));
+      Serial.write((uint8_t) (a0_sum & 0x00ff));
+      Serial.write((uint8_t)((a1_sum & 0xff00) >> 8));
+      Serial.write((uint8_t) (a1_sum & 0x00ff));
+      Serial.write(MSG_EOM1);
+      Serial.write(MSG_EOM2);
+
+      si5351.output_enable(SI5351_CLK0, 0); // disable clock output 0
+    }
+
+    // 5. send a measurement end message to the host
+    //    MSG_TYPE_MEAS_END_INFO
+    char* tmp = "     ";
+    sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
+                               MSG_TYPE_MEAS_END_INFO,
+                               MSG_EOM1, MSG_EOM2);
+    Serial.write(tmp);
+
+  } else {
+    // on error
+    char* tmp = "     ";
+    sprintf(tmp, "%c%c%c%c%c", MSG_SOM1, MSG_SOM2,
+                               MSG_TYPE_ANSWER_NOK,
+                               MSG_EOM1, MSG_EOM2);
+    Serial.write(tmp);
+  }
+
+}
+
+void cc_getConfig()
+{
+  Serial.write(MSG_SOM1);
+  Serial.write(MSG_SOM2);
+  Serial.write(MSG_TYPE_CONFIG);
+  Serial.write((uint8_t)((start_freq & 0xff000000) >> 24));
+  Serial.write((uint8_t)((start_freq & 0x00ff0000) >> 16));
+  Serial.write((uint8_t)((start_freq & 0x0000ff00) >>  8));
+  Serial.write((uint8_t) (start_freq & 0x000000ff));
+  Serial.write((uint8_t)((end_freq & 0xff000000) >> 24));
+  Serial.write((uint8_t)((end_freq & 0x00ff0000) >> 16));
+  Serial.write((uint8_t)((end_freq & 0x0000ff00) >>  8));
+  Serial.write((uint8_t) (end_freq & 0x000000ff));
+  Serial.write((uint8_t)((step_freq & 0xff000000) >> 24));
+  Serial.write((uint8_t)((step_freq & 0x00ff0000) >> 16));
+  Serial.write((uint8_t)((step_freq & 0x0000ff00) >>  8));
+  Serial.write((uint8_t) (step_freq & 0x000000ff));
+  Serial.write((uint8_t)((intervall & 0xff00) >> 8));
+  Serial.write((uint8_t) (intervall & 0x00ff));
+  Serial.write((uint8_t) drive_str);
+  Serial.write(MSG_EOM1);
+  Serial.write(MSG_EOM2);
 }
 
 /*****************************************************************************/
@@ -138,6 +306,7 @@ void cc_abort()
                              MSG_TYPE_ANSWER_NOK,
                              MSG_EOM1, MSG_EOM2);
   Serial.write(tmp);
+
   cc_init();
 }
 
diff --git a/firmware/firmware.ino b/firmware/firmware.ino
index 0d704a7..8bc1b56 100644
--- a/firmware/firmware.ino
+++ b/firmware/firmware.ino
@@ -10,8 +10,17 @@ extern "C" {
 
 Si5351 si5351;
 
+uint32_t start_freq = 10000;
+uint32_t   end_freq = 50000000;
+uint32_t  step_freq = 1000000; // 1 MHz default step size
+uint16_t  intervall = 1000; // intervall to change the frequency as milli seconds
+enum si5351_drive drive_str = SI5351_DRIVE_2MA;
+
 void setup()
 {
+  pinMode(A0, INPUT);
+  pinMode(A1, INPUT);
+
   // Init the serial connection
   Serial.begin(57600);
 
@@ -21,6 +30,13 @@ void setup()
   // init the Si5351
   si5351.init(SI5351_CRYSTAL_LOAD_8PF, 0);
 
+  si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
+
+  si5351.output_enable(SI5351_CLK0, 0); // disable clock output 0
+  si5351.output_enable(SI5351_CLK1, 0); // disable clock output 1
+  si5351.output_enable(SI5351_CLK2, 0); // disable clock output 2
+
+  /*
   // Set CLK0 to output 14 MHz with a fixed PLL frequency
   si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
   si5351.set_freq(1400000000ULL, SI5351_PLL_FIXED, SI5351_CLK0);
@@ -30,6 +46,7 @@ void setup()
   
   si5351.output_enable(SI5351_CLK0, 1); // enable clock output 0
   si5351.drive_strength(SI5351_CLK0, SI5351_DRIVE_2MA); // 2 4 6 8ma
+  */
 }
 
 void loop()
diff --git a/firmware/globals.h b/firmware/globals.h
index a6a1d29..fcf8a51 100644
--- a/firmware/globals.h
+++ b/firmware/globals.h
@@ -7,8 +7,11 @@
 #define MSG_EOM1 0x0d
 #define MSG_EOM2 0x0a
 
-#define MSG_TYPE_ANSWER_OK  0x01
-#define MSG_TYPE_ANSWER_NOK 0x02
+#define MSG_TYPE_ANSWER_OK        0x01
+#define MSG_TYPE_ANSWER_NOK       0x02
+#define MSG_TYPE_MEAS_FREQ_INFO   0x03
+#define MSG_TYPE_MEAS_END_INFO    0x04
+#define MSG_TYPE_CONFIG           0x05
 
 /*****************************************************************************/
 
@@ -32,7 +35,9 @@
 #define CC_CMD_SET_END_FREQ         0x02
 #define CC_CMD_SET_INTERVALL        0x03
 #define CC_CMD_SET_DRIVE_STRENGTH   0x04
-#define CC_CMD_START_MEASUREMENT    0x05
+#define CC_CMD_SET_FREQ_STEP        0x05
+#define CC_CMD_START_MEASUREMENT    0x06
+#define CC_CMD_GET_CONFIG           0x10
 
 /*****************************************************************************/
 
@@ -40,15 +45,19 @@
 #define CC_CMD_SET_END_FREQ_FUNC          &cc_setEndFreq
 #define CC_CMD_SET_INTERVALL_FUNC         &cc_setIntervall
 #define CC_CMD_SET_DRIVE_STRENGTH_FUNC    &cc_setDriveStrength
+#define CC_CMD_SET_FREQ_STEP_FUNC         &cc_setFreqStep
 #define CC_CMD_START_MEASUREMENT_FUNC     &cc_startMeasurement
+#define CC_CMD_GET_CONFIG_FUNC            &cc_getConfig
 
 /*****************************************************************************/
 
 #define CC_CMD_SET_START_FREQ_DATA_TO_READ      4 // up to 32 bit = 4 byte => 2 ** 32 = >500000000Hz
 #define CC_CMD_SET_END_FREQ_DATA_TO_READ        4 // up to 32 bit = 4 byte => 2 ** 32 = >500000000Hz
-#define CC_CMD_SET_INTERVALL_DATA_TO_READ       3 // up to 24 bit = 3 byte => 2 ** 24 =   >1000000Hz
+#define CC_CMD_SET_INTERVALL_DATA_TO_READ       2
 #define CC_CMD_SET_DRIVE_STRENGTH_DATA_TO_READ  1
+#define CC_CMD_SET_FREQ_STEP_DATA_TO_READ       4
 #define CC_CMD_START_MEASUREMENT_DATA_TO_READ   0
+#define CC_CMD_GET_CONFIG_DATA_TO_READ          0
 
 /*****************************************************************************/