Add some documentation to bridge_pwm block

controller/controller/block_bridge_pwm.c

@@ -33,6 +33,13 @@
      |             1  b   |----
      |	                  |
      ----------------------
+
+	This block generates an PWM signal based on the input value
+	which can be used to control a H-bridge.
+	
+	 0.0 <= in < 1.0	a = PWM modulated, b = false
+	-1.0 <= in < 0.0	a = false, b = PWM modulated
+	 0.0 == in		a = false, b = false;
      
  */
 
@@ -86,7 +93,14 @@ static void calculate(struct controller_block *bridge)
 }
 
 static struct controller_block_param_list params[] = {
+	/* Divider between sample frequency and PWM frequency. 
+	   This also influences the available number of PWM steps.
+	 */
 	{ "divider",       false },
+	/* Are we allowed to switch an output continuously on?
+	   Set this to false if the driver needs a switching output 
+	   for generating proper gate voltage.
+	 */
 	{ "continuous_on", false },
 	{ NULL },
 };