diff --git a/lambda/adc.h b/lambda/adc.h
index 3e8aac3..40a71fe 100644
--- a/lambda/adc.h
+++ b/lambda/adc.h
@@ -12,8 +12,11 @@
 #ifndef ADC_H_
 #define ADC_H_
 
+/** ADC ref voltage */
 #define AREF_MV 5000
+/** ADC nonlinearity offset at 0 mV voltage */
 #define ADC_NONLIN_0 -8
+/** ADC nonlinearity offset at ref voltage */
 #define ADC_NONLIN_AREF 12
 
 #if F_CPU == 1000000
diff --git a/lambda/airgate.c b/lambda/airgate.c
index c84b745..14bb445 100644
--- a/lambda/airgate.c
+++ b/lambda/airgate.c
@@ -6,7 +6,7 @@
  *
  *  Simple stepper motor control with a linear acceleration profile using the
  *  DRV8825. An absolute position from 0 to 255 can be set where 200 units
- *  correspond to 360° rotation (with 1.8 ° step angle).
+ *  correspond to 360° rotation (with 1.8° step angle).
  */
 
 #include <stdlib.h>
@@ -33,7 +33,7 @@
 static volatile uint8_t speed = MIN_SPEED;
 
 /**
- * Sets increased current for higher torque,sets the direction and initial
+ * Sets increased current for higher torque, sets the direction and initial
  * speed and starts the motor by starting the timer.
  */
 static void start(void) {
diff --git a/lambda/airgate.h b/lambda/airgate.h
index bc6693c..7a1059d 100644
--- a/lambda/airgate.h
+++ b/lambda/airgate.h
@@ -16,6 +16,10 @@
 /** Max value 255 for 8 bit timer and 65535 for 16 bit timer */
 #define MAX_SPEED 250
 
+/*
+ * Mapping of airgate position to absolute motor position in (full) steps
+ * (1.8° step angle)
+ */
 #define AIRGATE_CLOSE  	0
 #define AIRGATE_25	 	15
 #define AIRGATE_50 		30
@@ -34,7 +38,7 @@
 
 /**
  * Sets the airgate position 0 - 255, where 200 units correspond to 360°
- * rotation (with 1.8 ° step angle).
+ * rotation (with 1.8° step angle).
  */
 void setAirgate(uint8_t const position);