diff --git a/firmware/command_ctrl.ino b/firmware/command_ctrl.ino
index 1f79024..66184f6 100644
--- a/firmware/command_ctrl.ino
+++ b/firmware/command_ctrl.ino
@@ -201,7 +201,7 @@ void cc_startMeasurement()
     si5351.drive_strength(SI5351_CLK0, drive_str); // 2 4 6 8ma
 
     uint8_t t = 0;
-    for (t = 0; t < 200; t++)
+    for (t = 0; t < 100; t++)
     {
       uint16_t tmp = analogRead(A0);
                tmp = analogRead(A1);
@@ -225,13 +225,13 @@ void cc_startMeasurement()
         uint8_t t = 0;
         uint16_t ta0 = 0;
         uint16_t ta1 = 0;
-        for (t = 0; t < 20; t++)
+        for (t = 0; t < MEAS_LOOP_CNT; t++)
         {
           ta0 += analogRead(A0);
           ta1 += analogRead(A1);
         }
-        a0_sum += (ta0 / 20);
-        a1_sum += (ta1 / 20);
+        a0_sum += (ta0 / MEAS_LOOP_CNT);
+        a1_sum += (ta1 / MEAS_LOOP_CNT);
 
         delay(1);
       }
diff --git a/firmware/firmware.ino b/firmware/firmware.ino
index e9e9072..f6f84ad 100644
--- a/firmware/firmware.ino
+++ b/firmware/firmware.ino
@@ -21,8 +21,18 @@ enum si5351_drive drive_str = SI5351_DRIVE_2MA;
 
 void setup()
 {
-  pinMode(A0, INPUT);
-  pinMode(A1, INPUT);
+  // manage the analog pins
+  pinMode(A0, INPUT); // forward SWR measurement
+  pinMode(A1, INPUT); // backward SWR measurement
+  pinMode(A2, OUTPUT);
+  pinMode(A3, OUTPUT);
+  pinMode(A6, OUTPUT);
+  pinMode(A7, OUTPUT);
+
+  digitalWrite(A2, LOW);
+  digitalWrite(A3, LOW);
+  digitalWrite(A6, LOW);
+  digitalWrite(A7, LOW);
 
   // Init the serial connection
   Serial.begin(115200);
@@ -39,6 +49,8 @@ void setup()
   si5351.output_enable(SI5351_CLK1, 0); // disable clock output 1
   si5351.output_enable(SI5351_CLK2, 0); // disable clock output 2
 
+  analogReference(DEFAULT); // 5V reference
+
 }
 
 void loop()
@@ -70,4 +82,4 @@ void loop()
 
   delay(100);
 }
-
+
diff --git a/firmware/globals.h b/firmware/globals.h
index fcf8a51..4951059 100644
--- a/firmware/globals.h
+++ b/firmware/globals.h
@@ -1,6 +1,10 @@
 
 /*****************************************************************************/
 
+#define MEAS_LOOP_CNT 20
+
+/*****************************************************************************/
+
 /* Message byte definitions: */
 #define MSG_SOM1 0x3c
 #define MSG_SOM2 0x3e
@@ -64,4 +68,4 @@
 #define CC_READ_DATA_MAX 64
 
 /*****************************************************************************/
-
+