Fixed cooling fan support (M106 command)

Fixed M106 command so that the cooling fan is controllably by PWM and
works the right way round (0 = off, 1 = on). Also added optional P
parameter to specify the value that corresponds to maximum PWM.

Configuration.h

@@ -24,7 +24,7 @@ Licence: GPL
 #define CONFIGURATION_H
 
 #define NAME "RepRapFirmware"
-#define VERSION "0.57p-dc42"
+#define VERSION "0.57q-dc42"
 #define DATE "2014-02-24"
 #define LAST_AUTHOR "dc42"
 

GCodes.cpp

@@ -59,7 +59,9 @@ void GCodes::Init()
 	gCodeLetters = GCODE_LETTERS;
 	distanceScale = 1.0;
 	for (int8_t i = 0; i < DRIVES - AXES; i++)
+	{
 		lastPos[i] = 0.0;
+	}
 	fileBeingPrinted = NULL;
 	fileToPrint = NULL;
 	fileBeingWritten = NULL;
@@ -85,6 +87,7 @@ void GCodes::Init()
 	longWait = platform->Time();
 	dwellTime = longWait;
 	axisIsHomed[X_AXIS] = axisIsHomed[Y_AXIS] = axisIsHomed[Z_AXIS] = false;
+	fanMaxPwm = 1.0;
 }
 
 void GCodes::doFilePrint(GCodeBuffer* gb)
@@ -1580,8 +1583,16 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
 			break;
 
 		case 106: // Fan on or off
+			if (gb->Seen('P'))
+			{
+				// slic3r and Cura expect PWM values to go from 0 to 255, but we expect PWM value to go from 0.0 to 1.0.
+				// So I've added a P parameter to allow the top end of the range to be set, so we can be compatible with those programs.
+				fanMaxPwm = fmax(gb->GetFValue(), 1.0);
+			}
 			if (gb->Seen('S'))
-				platform->CoolingFan(gb->GetFValue());
+			{
+				platform->CoolingFan(fmax(gb->GetFValue(), 0.0)/fanMaxPwm);
+			}
 			break;
 
 		case 107: // Fan off - deprecated

GCodes.h

@@ -118,8 +118,8 @@ class GCodes
     bool SendConfigToLine();
     void WriteHTMLToFile(char b, GCodeBuffer *gb);
     bool OffsetAxes(GCodeBuffer *gb);
-
     int8_t Heater(int8_t head) const;
+
     Platform* platform;
     bool active;
     Webserver* webserver;
@@ -166,6 +166,7 @@ class GCodes
     bool zProbesSet;
     float longWait;
     bool axisIsHomed[3];	// these record which of the axes have been homed
+    float fanMaxPwm;		// the M106 S value that represents 100% fan speed
 };
 
 //*****************************************************************************************************

Platform.h

@@ -133,7 +133,7 @@ Licence: GPL
 #define TEMP_INTERVAL 0.122 // secs - check and control temperatures this often
 #define STANDBY_TEMPERATURES {ABS_ZERO, ABS_ZERO} // We specify one for the bed, though it's not needed
 #define ACTIVE_TEMPERATURES {ABS_ZERO, ABS_ZERO}
-#define COOLING_FAN_PIN 34
+#define COOLING_FAN_PIN X6
 #define HEAT_ON 0 // 0 for inverted heater (eg Duet v0.6) 1 for not (e.g. Duet v0.4)
 
 #define AD_RANGE 1023.0//16383 // The A->D converter that measures temperatures gives an int this big as its max value
@@ -899,7 +899,8 @@ inline void Platform::CoolingFan(float speed)
 {
 	if(coolingFanPin < 0)
 		return;
-	analogWrite(coolingFanPin, (uint8_t)(speed*255.0));
+	// The cooling fan output pin gets inverted
+	analogWriteNonDue(coolingFanPin, (uint32_t)((1.0 - speed)*255.0));
 }
 
 //inline void Platform::SetHeatOn(int8_t ho)