diff --git a/ardustim/ardustim/ardustim.ino b/ardustim/ardustim/ardustim.ino
index 3e52b13..39a3ecf 100644
--- a/ardustim/ardustim/ardustim.ino
+++ b/ardustim/ardustim/ardustim.ino
@@ -62,7 +62,7 @@ uint16_t sweep_rate = 1;
 sweep_step *SweepSteps;  /* Global pointer for the sweep steps */
 
 wheels Wheels[MAX_WHEELS] = {
-  /* Pointer to friendly name string, pointer to edge array, RPM Scaler, Number of edges in the array, whether the number of edges covers 360 or 720 degrees */
+   /* Pointer to friendly name string, pointer to edge array, RPM Scaler, Number of edges in the array, whether the number of edges covers 360 or 720 degrees */
   { dizzy_four_cylinder_friendly_name, dizzy_four_cylinder, 0.03333, 4, 360 },
   { dizzy_six_cylinder_friendly_name, dizzy_six_cylinder, 0.05, 6, 360 },
   { dizzy_eight_cylinder_friendly_name, dizzy_eight_cylinder, 0.06667, 8, 360 },
@@ -204,11 +204,13 @@ void setup() {
 
 //  pinMode(7, OUTPUT); /* Debug pin for Saleae to track sweep ISR execution speed */
   pinMode(8, OUTPUT); /* Primary (crank usually) output */
-  pinMode(9, OUTPUT); /* Secondary (cam usually) output */
-  pinMode(10, OUTPUT); /* Knock signal for seank, ony on LS1 pattern, NOT IMPL YET */
+  pinMode(9, OUTPUT); /* Secondary (cam1 usually) output */
+  pinMode(10, OUTPUT); /* Tertiary (cam2 usually) output */
+  pinMode(11, OUTPUT); /* Knock signal for seank, ony on LS1 pattern, NOT IMPL YET */
 #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
-  pinMode(53, OUTPUT); 
-  pinMode(52, OUTPUT); 
+  pinMode(53, OUTPUT); /* crank */
+  pinMode(52, OUTPUT); /* cam 1 */
+  pinMode(51, OUTPUT); /* untested - should be cam2*/
 #endif
 
   sei(); // Enable interrupts
diff --git a/ardustim/ardustim/wheel_defs.h b/ardustim/ardustim/wheel_defs.h
index b14cfbc..b9c6100 100644
--- a/ardustim/ardustim/wheel_defs.h
+++ b/ardustim/ardustim/wheel_defs.h
@@ -51,6 +51,18 @@
   * Most/all patterns show the pulses you're receive for one revolution
   * of a REAL wheel on a real engine.
   */
+
+  /*
+   * Values to use within a wheel definition. 
+   * 0 means no tooth on any wheel definition
+   * 1 means crank tooth
+   * 2 means cam1 tooth
+   * 4 means cam2 tooth
+   * 
+   * combinations of numbers mean all of the related teeth are present, 
+   * eg  3 means crank and cam1, 5 means crank and cam2, 6 means cam1 and cam2, 7 means crank, cam1 and cam2 
+   */
+
   
   /* Wheel types we know about...
    * This enumerations is the INDEX into the Wheels[] array of structures