Queued fan control. Issue #90

Marlin/Marlin.h

 extern bool axis_relative_modes[];
 extern float current_position[NUM_AXIS] ;
 extern float add_homeing[3];
+extern unsigned char FanSpeed;
 
 // Handling multiple extruders pins
 extern uint8_t active_extruder;

Marlin/Marlin.pde

 float current_position[NUM_AXIS] = { 0.0, 0.0, 0.0, 0.0 };
 float add_homeing[3]={0,0,0};
 uint8_t active_extruder = 0;
+unsigned char FanSpeed=0;
 
 //===========================================================================
 //=============================private variables=============================
 static bool relative_mode = false;  //Determines Absolute or Relative Coordinates
 static bool relative_mode_e = false;  //Determines Absolute or Relative E Codes while in Absolute Coordinates mode. E is always relative in Relative Coordinates mode.
 
-static uint8_t fanpwm=0;
-
 static char cmdbuffer[BUFSIZE][MAX_CMD_SIZE];
 static bool fromsd[BUFSIZE];
 static int bufindr = 0;
     #if FAN_PIN > -1
       case 106: //M106 Fan On
         if (code_seen('S')){
-            WRITE(FAN_PIN,HIGH);
-            fanpwm=constrain(code_value(),0,255);
-            analogWrite(FAN_PIN,  fanpwm);
+           FanSpeed=constrain(code_value(),0,255);
         }
         else {
-          WRITE(FAN_PIN,HIGH);
-          fanpwm=255;
-          analogWrite(FAN_PIN, fanpwm);			
+          FanSpeed=255;			
         }
         break;
       case 107: //M107 Fan Off
-        WRITE(FAN_PIN,LOW);
-        analogWrite(FAN_PIN, 0);
+        FanSpeed = 0;
         break;
     #endif //FAN_PIN
 

Marlin/planner.cpp

   unsigned char y_active = 0;  
   unsigned char z_active = 0;
   unsigned char e_active = 0;
+  unsigned char fan_speed = 0;
+  unsigned char tail_fan_speed = 0;
   block_t *block;
 
   if(block_buffer_tail != block_buffer_head) {
     uint8_t block_index = block_buffer_tail;
+    tail_fan_speed = block_buffer[block_index].fan_speed;
     while(block_index != block_buffer_head) {
       block = &block_buffer[block_index];
       if(block->steps_x != 0) x_active++;
       if(block->steps_y != 0) y_active++;
       if(block->steps_z != 0) z_active++;
       if(block->steps_e != 0) e_active++;
+      if(block->fan_speed != 0) fan_speed++;
       block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1);
     }
   }
+  else {
+    if (FanSpeed != 0) analogWrite(FAN_PIN,FanSpeed); // If buffer is empty use current fan speed
+  }
   if((DISABLE_X) && (x_active == 0)) disable_x();
   if((DISABLE_Y) && (y_active == 0)) disable_y();
   if((DISABLE_Z) && (z_active == 0)) disable_z();
   if((DISABLE_E) && (e_active == 0)) { disable_e0();disable_e1();disable_e2(); }
+  if((FanSpeed == 0) && (fan_speed ==0)) analogWrite(FAN_PIN, 0);
+  if (FanSpeed != 0 && tail_fan_speed !=0) { 
+    analogWrite(FAN_PIN,tail_fan_speed);
+  }
 }
 
 
   // Bail if this is a zero-length block
   if (block->step_event_count <=dropsegments) { return; };
 
+  block->fan_speed = FanSpeed;
+  
   // Compute direction bits for this block 
   block->direction_bits = 0;
   if (target[X_AXIS] < position[X_AXIS]) { block->direction_bits |= (1<<X_AXIS); }

Marlin/planner.h

   unsigned long initial_rate;                        // The jerk-adjusted step rate at start of block  
   unsigned long final_rate;                          // The minimal rate at exit
   unsigned long acceleration_st;                     // acceleration steps/sec^2
+  unsigned long fan_speed;
   volatile char busy;
 } block_t;
 

Marlin/stepper.cpp

 /* The timer calculations of this module informed by the 'RepRap cartesian firmware' by Zack Smith
    and Philipp Tiefenbacher. */
 
-
-
-
 #include "Marlin.h"
 #include "stepper.h"
 #include "planner.h"
       counter_y = counter_x;
       counter_z = counter_x;
       counter_e = counter_x;
-      step_events_completed = 0;
+      step_events_completed = 0; 
+      
       #ifdef Z_LATE_ENABLE 
         if(current_block->steps_z > 0) {
           enable_z();

Marlin/ultralcd.pde

         if(force_lcd_update)
         {
           lcd.setCursor(0,line);lcdprintPGM(MSG_FAN_SPEED);
-          lcd.setCursor(13,line);lcd.print(ftostr3(fanpwm));
+          lcd.setCursor(13,line);lcd.print(ftostr3(FanSpeed));
         }
         
         if((activeline!=line) )
           linechanging=!linechanging;
           if(linechanging)
           {
-              encoderpos=fanpwm;
+              encoderpos=FanSpeed;
           }
           else
           {
         {
           if(encoderpos<0) encoderpos=0;
           if(encoderpos>255) encoderpos=255;
-          fanpwm=encoderpos;
-            analogWrite(FAN_PIN,  fanpwm);
+          FanSpeed=encoderpos;
+            analogWrite(FAN_PIN,  FanSpeed);
           lcd.setCursor(13,line);lcd.print(itostr3(encoderpos));
         }
         
         if(force_lcd_update)
         {
           lcd.setCursor(0,line);lcdprintPGM(MSG_FAN_SPEED);
-          lcd.setCursor(13,line);lcd.print(ftostr3(fanpwm));
+          lcd.setCursor(13,line);lcd.print(ftostr3(FanSpeed));
         }
         
         if((activeline!=line) )
           linechanging=!linechanging;
           if(linechanging)
           {
-              encoderpos=fanpwm;
+              encoderpos=FanSpeed;
           }
           else
           {
         {
           if(encoderpos<0) encoderpos=0;
           if(encoderpos>255) encoderpos=255;
-          fanpwm=encoderpos;
-            analogWrite(FAN_PIN,  fanpwm);
+          FanSpeed=encoderpos;
+            analogWrite(FAN_PIN,  FanSpeed);
           lcd.setCursor(13,line);lcd.print(itostr3(encoderpos));
         }