zero duty cycle fix

include/pwm.h

 #define SENSOR1 15
 #define SENSOR2 12
 
+#define INT_TIME 20         // interrupt intervall [ms]
 class Treppe {
     private:
     uint8_t stairs;
-    uint16_t time_per_stair = 300;          // dimmtime per stair [ms]
-    uint16_t idle_brightness = 200;
-    uint16_t active_brightness = 2048;
+    uint16_t time_per_stair = 200;          // dimmtime per stair [ms]
+    uint16_t idle_brightness = 0;
+    uint16_t active_brightness = 1048;
 
     uint8_t direction = 0;
     uint8_t switch_direction = 0;

src/pwm.cpp

       pwmController.setChannelPWM(led, (uint16_t)startval);
       lastled = led;
       current_pwm = startval;
-      stepsize = 20*abs(stopval - startval)/(float)time_per_stair;      // only valid at 1ms function call interval
+      stepsize = INT_TIME*abs(stopval - startval)/(float)time_per_stair;      // only valid at 1ms function call interval
       return 1;
     }
     
-    if(current_pwm > stopval - stepsize && current_pwm < stopval + stepsize) return 0;
-    // todo: duty cycle zero!
     if(startval > stopval){
       current_pwm -= stepsize;
     }
     }
     Serial.println((uint16_t)current_pwm);
     pwmController.setChannelPWM(led, (uint16_t)current_pwm);
+    if(current_pwm > stopval - stepsize && current_pwm < stopval + stepsize){
+      if(stopval == 0) pwmController.setChannelPWM(led, 0);
+      return 0;
+    } 
     return 1;
 }