Allow heaters to stay full On when PWM=127

In previous version, even with PWM = 127, the system turns the FET off
and then on in the next cycle. This bevavior may increase the FET heat
dissipation.
It was fixed keeping the FET always On when PWM=127.

Marlin/temperature.cpp

@@ -1057,41 +1057,42 @@ ISR(TIMER0_COMPB_vect)
       #ifdef HEATERS_PARALLEL
       WRITE(HEATER_1_PIN,1);
       #endif
-    }
+    } else WRITE(HEATER_0_PIN,0);
+
     #if EXTRUDERS > 1
     soft_pwm_1 = soft_pwm[1];
-    if(soft_pwm_1 > 0) WRITE(HEATER_1_PIN,1);
+    if(soft_pwm_1 > 0) WRITE(HEATER_1_PIN,1); else WRITE(HEATER_1_PIN,0);
     #endif
     #if EXTRUDERS > 2
     soft_pwm_2 = soft_pwm[2];
-    if(soft_pwm_2 > 0) WRITE(HEATER_2_PIN,1);
+    if(soft_pwm_2 > 0) WRITE(HEATER_2_PIN,1); else WRITE(HEATER_2_PIN,0);
     #endif
     #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
     soft_pwm_b = soft_pwm_bed;
-    if(soft_pwm_b > 0) WRITE(HEATER_BED_PIN,1);
+    if(soft_pwm_b > 0) WRITE(HEATER_BED_PIN,1); else WRITE(HEATER_BED_PIN,0);
     #endif
     #ifdef FAN_SOFT_PWM
     soft_pwm_fan = fanSpeedSoftPwm / 2;
-    if(soft_pwm_fan > 0) WRITE(FAN_PIN,1);
+    if(soft_pwm_fan > 0) WRITE(FAN_PIN,1); else WRITE(FAN_PIN,0);
     #endif
   }
-  if(soft_pwm_0 <= pwm_count) { 
+  if(soft_pwm_0 < pwm_count) { 
       WRITE(HEATER_0_PIN,0);
       #ifdef HEATERS_PARALLEL
       WRITE(HEATER_1_PIN,0);
       #endif
     }
   #if EXTRUDERS > 1
-  if(soft_pwm_1 <= pwm_count) WRITE(HEATER_1_PIN,0);
+  if(soft_pwm_1 < pwm_count) WRITE(HEATER_1_PIN,0);
   #endif
   #if EXTRUDERS > 2
-  if(soft_pwm_2 <= pwm_count) WRITE(HEATER_2_PIN,0);
+  if(soft_pwm_2 < pwm_count) WRITE(HEATER_2_PIN,0);
   #endif
   #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
-  if(soft_pwm_b <= pwm_count) WRITE(HEATER_BED_PIN,0);
+  if(soft_pwm_b < pwm_count) WRITE(HEATER_BED_PIN,0);
   #endif
   #ifdef FAN_SOFT_PWM
-  if(soft_pwm_fan <= pwm_count) WRITE(FAN_PIN,0);
+  if(soft_pwm_fan < pwm_count) WRITE(FAN_PIN,0);
   #endif
 
   pwm_count += (1 << SOFT_PWM_SCALE);