path: root/src/Platform.h

/****************************************************************************************************

RepRapFirmware - Platform: RepRapPro Ormerod with Duet controller

Platform contains all the code and definitions to deal with machine-dependent things such as control
pins, bed area, number of extruders, tolerable accelerations and speeds and so on.

No definitions that are system-independent should go in here.  Put them in Configuration.h.  Note that
the lengths of arrays such as DRIVES (see below) are defined here, so any array initialiser that depends on those
lengths, for example:

#define DRIVES 4
.
.
.
#define DRIVE_RELATIVE_MODES {false, false, false, true}

also needs to go here.

-----------------------------------------------------------------------------------------------------

Version 0.3

28 August 2013

Adrian Bowyer
RepRap Professional Ltd
http://reprappro.com

Licence: GPL

****************************************************************************************************/

#ifndef PLATFORM_H
#define PLATFORM_H

// Language-specific includes

#include <cctype>
#include <cstring>
#include <malloc.h>
#include <cstdlib>
#include <climits>

// Platform-specific includes

#include "Arduino.h"
#include "SamNonDuePin.h"
#include "OutputMemory.h"
#include "SD_HSMCI.h"
#include "MAX31855.h"
#include "MCP4461.h"
#include "MassStorage.h"
#include "FileStore.h"

// Definitions needed by Pins.h

typedef int8_t Pin;								// type used to represent a pin number, negative means no pin

const bool FORWARDS = true;
const bool BACKWARDS = !FORWARDS;

#include "Pins.h"

/**************************************************************************************************/

// Some numbers...

#define TIME_TO_REPRAP 1.0e6 	// Convert seconds to the units used by the machine (usually microseconds)
#define TIME_FROM_REPRAP 1.0e-6 // Convert the units used by the machine (usually microseconds) to seconds

/**************************************************************************************************/


const int Z_PROBE_AD_VALUE = 400;						// Default for the Z probe - should be overwritten by experiment
const float Z_PROBE_STOP_HEIGHT = 0.7;					// Millimetres
const bool Z_PROBE_AXES[AXES] = { true, false, true };	// Axes for which the Z-probe is normally used
const unsigned int Z_PROBE_AVERAGE_READINGS = 8;		// We average this number of readings with IR on, and the same number with IR off

#if SUPPORT_INKJET

// Inkjet (if any - no inkjet is flagged by INKJET_BITS negative)

const int8_t INKJET_BITS = 12;							// How many nozzles? Set to -1 to disable this feature
const int INKJET_FIRE_MICROSECONDS = 5;					// How long to fire a nozzle
const int INKJET_DELAY_MICROSECONDS = 800;				// How long to wait before the next bit

#endif

const float MAX_FEEDRATES[DRIVES] = DRIVES_(100.0, 100.0, 3.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0);						// mm/sec
const float ACCELERATIONS[DRIVES] = DRIVES_(500.0, 500.0, 20.0, 250.0, 250.0, 250.0, 250.0, 250.0, 250.0);				// mm/sec^2
const float DRIVE_STEPS_PER_UNIT[DRIVES] = DRIVES_(87.4890, 87.4890, 4000.0, 420.0, 420.0, 420.0, 420.0, 420.0, 420.0);	// steps/mm
const float INSTANT_DVS[DRIVES] = DRIVES_(15.0, 15.0, 0.2, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0);								// mm/sec

// AXES

const size_t X_AXIS = 0, Y_AXIS = 1, Z_AXIS = 2, E0_AXIS = 3;	// The indices of the Cartesian axes in drive arrays
const size_t A_AXIS = 0, B_AXIS = 1, C_AXIS = 2;				// The indices of the 3 tower motors of a delta printer in drive arrays

const float AXIS_MINIMA[AXES] = { 0.0, 0.0, 0.0 };				// mm
const float AXIS_MAXIMA[AXES] = { 230.0, 210.0, 200.0 };		// mm

const float defaultPrintRadius = 50;							// mm
const float defaultDeltaHomedHeight = 200;						// mm

// HEATERS - The bed is assumed to be the at index 0

// Bed thermistor: http://uk.farnell.com/epcos/b57863s103f040/sensor-miniature-ntc-10k/dp/1299930?Ntt=129-9930
// Hot end thermistor: http://www.digikey.co.uk/product-search/en?x=20&y=11&KeyWords=480-3137-ND
const float defaultThermistorBetas[HEATERS] = HEATERS_(BED_BETA, EXT_BETA, EXT_BETA, EXT_BETA, EXT_BETA, EXT_BETA, EXT_BETA); // Bed thermistor: B57861S104F40; Extruder thermistor: RS 198-961
const float defaultThermistorSeriesRs[HEATERS] = HEATERS_(THERMISTOR_SERIES_RS, THERMISTOR_SERIES_RS, THERMISTOR_SERIES_RS,
													THERMISTOR_SERIES_RS, THERMISTOR_SERIES_RS, THERMISTOR_SERIES_RS, THERMISTOR_SERIES_RS);
const float defaultThermistor25RS[HEATERS] = HEATERS_(BED_R25, EXT_R25, EXT_R25, EXT_R25, EXT_R25, EXT_R25, EXT_R25); // Thermistor ohms at 25 C = 298.15 K

// Note on hot end PID parameters:
// The system is highly nonlinear because the heater power is limited to a maximum value and cannot go negative.
// If we try to run a traditional PID when there are large temperature errors, this causes the I-accumulator to go out of control,
// which causes a large amount of overshoot at lower temperatures. There are at least two ways of avoiding this:
//
// 1. Allow the PID to operate even with very large errors, but choose a very small I-term, just the right amount so that when heating up
//    from cold, the I-accumulator is approximately the value needed to maintain the correct power when the target temperature is reached.
//    This works well most of the time. However if the Duet board is reset when the extruder is hot and is then
//    commanded to heat up again before the extruder has cooled, the I-accumulator doesn't grow large enough, so the
//    temperature undershoots. The small value of the I-term then causes it to take a long time to reach the correct temperature.
//
// 2. Only allow the PID to operate when the temperature error is small enough for the PID to operate in the linear region.
//    So we set FULL_PID_BAND to a small value. It needs to be at least 15C because that is how much the temperature overshoots by
//    on an Ormerod when we turn the heater off from full power at about 180C. When we transition to PID, we set the I-term to the
//    value we expect to be needed to maintain the target temperature. We use an additional T parameter to allow this value to be
//    estimated.
//
// The default values use method (2).
//
// Note: a negative P, I or D value means do not use PID for this heater, use bang-bang control instead.
// This allows us to switch between PID and bang-bang using the M301 and M304 commands.

// We use method 2 (see above)
const float defaultPidKis[HEATERS] = HEATERS_(5.0, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2); 			// Integral PID constants
const float defaultPidKds[HEATERS] = HEATERS_(500.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0); // Derivative PID constants
const float defaultPidKps[HEATERS] = HEATERS_(-1.0, 10.0, 10.0, 10.0, 10.0, 10.0, 10.0);	// Proportional PID constants, negative values indicate use bang-bang instead of PID
const float defaultPidKts[HEATERS] = HEATERS_(2.7, 0.4, 0.4, 0.4, 0.4, 0.4, 0.4);			// approximate PWM value needed to maintain temperature, per degC above room temperature
const float defaultPidKss[HEATERS] = HEATERS_(1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0);			// PWM scaling factor, to allow for variation in heater power and supply voltage
const float defaultFullBands[HEATERS] = HEATERS_(5.0, 30.0, 30.0, 30.0, 30.0, 30.0, 30.0);	// errors larger than this cause heater to be on or off
const float defaultPidMins[HEATERS] = HEATERS_(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0);			// minimum value of I-term
const float defaultPidMaxes[HEATERS] = HEATERS_(255, 180, 180, 180, 180, 180, 180);			// maximum value of I-term, must be high enough to reach 245C for ABS printing

const float STANDBY_TEMPERATURES[HEATERS] = HEATERS_(ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO); // We specify one for the bed, though it's not needed
const float ACTIVE_TEMPERATURES[HEATERS] = HEATERS_(ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO, ABS_ZERO);

// For the theory behind ADC oversampling, see http://www.atmel.com/Images/doc8003.pdf
const unsigned int AD_OVERSAMPLE_BITS = 1;		// Number of bits we oversample when reading temperatures

// Define the number of temperature readings we average for each thermistor. This should be a power of 2 and at least 4 ** AD_OVERSAMPLE_BITS.
// Keep THERMISTOR_AVERAGE_READINGS * NUM_HEATERS * 2ms no greater than HEAT_SAMPLE_TIME or the PIDs won't work well.
const unsigned int THERMISTOR_AVERAGE_READINGS = 32;
const unsigned int AD_RANGE_REAL = 4095;													// The ADC that measures temperatures gives an int this big as its max value
const unsigned int AD_RANGE_VIRTUAL = ((AD_RANGE_REAL + 1) << AD_OVERSAMPLE_BITS) - 1;		// The max value we can get using oversampling
const unsigned int AD_DISCONNECTED_REAL = AD_RANGE_REAL - 3;								// We consider an ADC reading at/above this value to indicate that the thermistor is disconnected
const unsigned int AD_DISCONNECTED_VIRTUAL = AD_DISCONNECTED_REAL << AD_OVERSAMPLE_BITS;

const uint32_t maxPidSpinDelay = 5000;			// Maximum elapsed time in milliseconds between successive temp samples by Pid::Spin() permitted for a temp sensor

const size_t BED_HEATER = 0;					// Index of the heated bed
const size_t E0_HEATER = 1;						// Index of the first extruder heater

/****************************************************************************************************/

// File handling

const size_t MAX_FILES = 10;					// Must be large enough to handle the max number of simultaneous web requests + files being printed

const size_t FILE_BUFFER_SIZE = 256;

/****************************************************************************************************/

enum class BoardType : uint8_t
{
	Auto = 0,
	Duet_06 = 1,
	Duet_07 = 2,
	Duet_085 = 3
};

enum class EndStopHit
{
  noStop = 0,		// no endstop hit
  lowHit = 1,		// low switch hit, or Z-probe in use and above threshold
  highHit = 2,		// high stop hit
  lowNear = 3		// approaching Z-probe threshold
};

// The values of the following enumeration must tally with the definitions for the M574 command
enum class EndStopType
{
	noEndStop = 0,
	lowEndStop = 1,
	highEndStop = 2
};

/***************************************************************************************************/

// Enumeration describing the reasons for a software reset.
// The spin state gets or'ed into this, so keep the lower ~4 bits unused.
enum class SoftwareResetReason : uint16_t
{
	user = 0,					// M999 command
	erase = 55,					// special M999 command to erase firmware and reset
	inAuxOutput = 0x0800,		// this bit is or'ed in if we were in aux output at the time
	stuckInSpin = 0x1000,		// we got stuck in a Spin() function for too long
	inLwipSpin = 0x2000,		// we got stuck in a call to LWIP for too long
	inUsbOutput = 0x4000		// this bit is or'ed in if we were in USB output at the time
};

// Enumeration to describe various tests we do in response to the M111 command
enum class DiagnosticTestType : int
{
	TestWatchdog = 1001,			// test that we get a watchdog reset if the tick interrupt stops
	TestSpinLockup = 1002,			// test that we get a software reset if a Spin() function takes too long
	TestSerialBlock = 1003			// test what happens when we write a blocking message via debugPrintf()
};

// Info returned by FindFirst/FindNext calls
class FileInfo
{
public:

	bool isDirectory;
	unsigned long size;
	uint8_t day;
	uint8_t month;
	uint16_t year;
	char fileName[FILENAME_LENGTH];
};

/***************************************************************************************************************/

// Struct for holding Z probe parameters

struct ZProbeParameters
{
	int adcValue;					// the target ADC value
	float xOffset, yOffset;			// the offset of the probe relative to the print head
	float height;					// the nozzle height at which the target ADC value is returned
	float calibTemperature;			// the temperature at which we did the calibration
	float temperatureCoefficient;	// the variation of height with bed temperature
	float diveHeight;				// the dive height we use when probing
	float probeSpeed;				// the initial speed of probing
	float travelSpeed;				// the speed at which we travel to the probe point
	float param1, param2;			// extra parameters used by some types of probe e.g. Delta probe

	void Init(float h)
	{
		adcValue = Z_PROBE_AD_VALUE;
		xOffset = yOffset = 0.0;
		height = h;
		calibTemperature = 20.0;
		temperatureCoefficient = 0.0;	// no default temperature correction
		diveHeight = DEFAULT_Z_DIVE;
		probeSpeed = DEFAULT_PROBE_SPEED;
		travelSpeed = DEFAULT_TRAVEL_SPEED;
		param1 = param2 = 0.0;
	}

	float GetStopHeight(float temperature) const
	{
		return ((temperature - calibTemperature) * temperatureCoefficient) + height;
	}

	bool operator==(const ZProbeParameters& other) const
	{
		return adcValue == other.adcValue
				&& height == other.height
				&& xOffset == other.xOffset
				&& yOffset == other.yOffset
				&& calibTemperature == other.calibTemperature
				&& temperatureCoefficient == other.temperatureCoefficient
				&& diveHeight == other.diveHeight
				&& probeSpeed == other.probeSpeed
				&& travelSpeed == other.travelSpeed
				&& param1 == other.param1
				&& param2 == other.param2;
	}

	bool operator!=(const ZProbeParameters& other) const
	{
		return !operator==(other);
	}
};

class PidParameters
{
	// If you add any more variables to this class, don't forget to change the definition of operator== in Platform.cpp!
private:
	float thermistorBeta, thermistorInfR;				// private because these must be changed together

public:
	float kI, kD, kP, kT, kS;
	float fullBand, pidMin, pidMax;
	float thermistorSeriesR;
	float adcLowOffset, adcHighOffset;

	float GetBeta() const { return thermistorBeta; }
	float GetRInf() const { return thermistorInfR; }

	bool UsePID() const;
	float GetThermistorR25() const;
	void SetThermistorR25AndBeta(float r25, float beta);

	bool operator==(const PidParameters& other) const;
	bool operator!=(const PidParameters& other) const
	{
		return !operator==(other);
	}
};

// Class to perform averaging of values read from the ADC
// numAveraged should be a power of 2 for best efficiency

template<size_t numAveraged> class AveragingFilter
{
public:
	AveragingFilter()
	{
		Init(0);
	}

	void Init(uint16_t val) volatile
	{
		irqflags_t flags = cpu_irq_save();
		sum = (uint32_t)val * (uint32_t)numAveraged;
		index = 0;
		isValid = false;
		for (size_t i = 0; i < numAveraged; ++i)
		{
			readings[i] = val;
		}
		cpu_irq_restore(flags);
	}

	// Call this to put a new reading into the filter
	// This is only called by the ISR, so it not declared volatile to make it faster
	void ProcessReading(uint16_t r)
	{
		sum = sum - readings[index] + r;
		readings[index] = r;
		++index;
		if (index == numAveraged)
		{
			index = 0;
			isValid = true;
		}
	}

	// Return the raw sum
	uint32_t GetSum() const volatile
	{
		return sum;
	}

	// Return true if we have a valid average
	bool IsValid() const volatile
	{
		return isValid;
	}

private:
	uint16_t readings[numAveraged];
	size_t index;
	uint32_t sum;
	bool isValid;
	//invariant(sum == + over readings)
	//invariant(index < numAveraged)
};

typedef AveragingFilter<THERMISTOR_AVERAGE_READINGS> ThermistorAveragingFilter;
typedef AveragingFilter<Z_PROBE_AVERAGE_READINGS> ZProbeAveragingFilter;

// Enumeration of error condition bits
enum class ErrorCode : uint32_t
{
	BadTemp = 1 << 0,
	BadMove = 1 << 1,
	OutputStarvation = 1 << 2,
	OutputStackOverflow = 1 << 3
};

// Different types of hardware-related input-output
enum class SerialSource
{
	USB,
	AUX,
	AUX2
};

// Supported message destinations
enum MessageType
{
	AUX_MESSAGE,						// Type byte of a message that is to be sent to the first auxiliary device
	AUX2_MESSAGE,						// Type byte of a message that is to be sent to the second auxiliary device
	FLASH_LED,							// Type byte of a message that is to flash an LED; the next two bytes define the frequency and M/S ratio
	DISPLAY_MESSAGE,					// Type byte of a message that is to appear on a local display; the L is not displayed; \f and \n should be supported
	HOST_MESSAGE,						// Type byte of a message that is to be sent in non-blocking mode to the host via USB
	DEBUG_MESSAGE,						// Type byte of a debug message to send in blocking mode to USB
	HTTP_MESSAGE,						// Type byte of a message that is to be sent to the web (HTTP)
	TELNET_MESSAGE,						// Type byte of a message that is to be sent to a Telnet client
	GENERIC_MESSAGE,					// Type byte of a message that is to be sent to the web & host
};

// The main class that defines the RepRap machine for the benefit of the other classes

class Platform
{   
public:
	// Enumeration to describe the status of a drive
	enum class DriveStatus : uint8_t { disabled, idle, enabled };
  
	// Error results generated by GetTemperature()
	enum class TempError : uint8_t { errOk, errShort, errShortVcc, errShortGnd, errOpen, errTooHigh, errTimeout, errIO };

	Platform();
  
//-------------------------------------------------------------------------------------------------------------

	// These are the functions that form the interface between Platform and the rest of the firmware.

	void Init();									// Set the machine up after a restart.  If called subsequently this should set the machine up as if
													// it has just been restarted; it can do this by executing an actual restart if you like, but beware the loop of death...
	void Spin();									// This gets called in the main loop and should do any housekeeping needed
	void Exit();									// Shut down tidily. Calling Init after calling this should reset to the beginning

	static void EnableWatchdog();
	static void KickWatchdog();						// kick the watchdog

	Compatibility Emulating() const;
	void SetEmulating(Compatibility c);
	void Diagnostics();
	void DiagnosticTest(int d);
	void ClassReport(float &lastTime);  			// Called on Spin() return to check everything's live.
	void RecordError(ErrorCode ec) { errorCodeBits |= (uint32_t)ec; }
	void SoftwareReset(uint16_t reason);
	bool AtxPower() const;
	void SetAtxPower(bool on);
	void SetBoardType(BoardType bt);
	const char* GetElectronicsString() const;

	// Timing
  
	float Time();									// Returns elapsed seconds since some arbitrary time
	static uint32_t GetInterruptClocks();			// Get the interrupt clock count
	static bool ScheduleInterrupt(uint32_t tim);	// Schedule an interrupt at the specified clock count, or return true if it has passed already
	void Tick();
  
  	// Communications and data storage
  
	bool GCodeAvailable(const SerialSource source) const;
	char ReadFromSource(const SerialSource source);

	void SetIPAddress(uint8_t ip[]);
	const uint8_t* IPAddress() const;
	void SetNetMask(uint8_t nm[]);
	const uint8_t* NetMask() const;
	void SetGateWay(uint8_t gw[]);
	const uint8_t* GateWay() const;
	void SetMACAddress(uint8_t mac[]);
	const uint8_t* MACAddress() const;
	void SetBaudRate(size_t chan, uint32_t br);
	uint32_t GetBaudRate(size_t chan) const;
	void SetCommsProperties(size_t chan, uint32_t cp);
	uint32_t GetCommsProperties(size_t chan) const;

	friend class FileStore;

	MassStorage* GetMassStorage();
	FileStore* GetFileStore(const char* directory, const char* fileName, bool write);
	const char* GetWebDir() const; 	// Where the htm etc files are
	const char* GetGCodeDir() const; 	// Where the gcodes are
	const char* GetSysDir() const;  	// Where the system files are
	const char* GetMacroDir() const;		// Where the user-defined macros are
	const char* GetConfigFile() const; // Where the configuration is stored (in the system dir).
	const char* GetDefaultFile() const;	// Where the default configuration is stored (in the system dir).
	void InvalidateFiles();					// Called to invalidate files when the SD card is removed

	// Message output (see MessageType for further details)

	void Message(const MessageType type, const char *message);
	void Message(const MessageType type, const StringRef& message);
	void Message(const MessageType type, OutputBuffer *buffer);
	void MessageF(const MessageType type, const char *fmt, ...);
	void MessageF(const MessageType type, const char *fmt, va_list vargs);

	// Movement

	void EmergencyStop();
	void SetPhysicalDrive(size_t driverNumber, int8_t physicalDrive);
	int GetPhysicalDrive(size_t driverNumber) const;
	void SetDirection(size_t drive, bool direction);
	void SetDirectionValue(size_t drive, bool dVal);
	bool GetDirectionValue(size_t drive) const;
	void SetEnableValue(size_t drive, bool eVal);
	bool GetEnableValue(size_t drive) const;
	void StepHigh(size_t drive);
	void StepLow(size_t drive);
	void EnableDrive(size_t drive);
	void DisableDrive(size_t drive);
	void SetDrivesIdle();
	void SetMotorCurrent(size_t drive, float current);
	float MotorCurrent(size_t drive) const;
	void SetIdleCurrentFactor(float f);
	float GetIdleCurrentFactor() const { return idleCurrentFactor; }
	bool SetMicrostepping(size_t drive, int microsteps, int mode);
	unsigned int GetMicrostepping(size_t drive, bool& interpolation) const;
	float DriveStepsPerUnit(size_t drive) const;
	const float *GetDriveStepsPerUnit() const { return driveStepsPerUnit; }
	void SetDriveStepsPerUnit(size_t drive, float value);
	float Acceleration(size_t drive) const;
	const float* Accelerations() const;
	void SetAcceleration(size_t drive, float value);
	float MaxFeedrate(size_t drive) const;
	const float* MaxFeedrates() const;
	void SetMaxFeedrate(size_t drive, float value);
	float ConfiguredInstantDv(size_t drive) const;
	float ActualInstantDv(size_t drive) const;
	void SetInstantDv(size_t drive, float value);
	EndStopHit Stopped(size_t drive) const;
	float AxisMaximum(size_t axis) const;
	void SetAxisMaximum(size_t axis, float value);
	float AxisMinimum(size_t axis) const;
	void SetAxisMinimum(size_t axis, float value);
	float AxisTotalLength(size_t axis) const;
	float GetElasticComp(size_t drive) const;
	void SetElasticComp(size_t extruder, float factor);
	void SetEndStopConfiguration(size_t axis, EndStopType endstopType, bool logicLevel);
	void GetEndStopConfiguration(size_t axis, EndStopType& endstopType, bool& logicLevel) const;

	// Z probe

	float ZProbeStopHeight() const;
	float GetZProbeDiveHeight() const;
	float GetZProbeTravelSpeed() const;
	int ZProbe() const;
	EndStopHit GetZProbeResult() const;
	int GetZProbeSecondaryValues(int& v1, int& v2);
	void SetZProbeType(int iZ);
	int GetZProbeType() const;
	void SetZProbeAxes(const bool axes[AXES]);
	void GetZProbeAxes(bool (&axes)[AXES]);
	const ZProbeParameters& GetZProbeParameters() const;
	bool SetZProbeParameters(const struct ZProbeParameters& params);
	bool MustHomeXYBeforeZ() const;

	void SetExtrusionAncilliaryPWM(float v);
	float GetExtrusionAncilliaryPWM() const;
	void ExtrudeOn();
	void ExtrudeOff();

	size_t SlowestDrive() const;

	// Heat and temperature

	float GetTemperature(size_t heater, TempError* err = nullptr) const; // Result is in degrees Celsius
	void SetHeater(size_t heater, float power);				// power is a fraction in [0,1]
	float HeatSampleTime() const;
	void SetHeatSampleTime(float st);
	void SetPidParameters(size_t heater, const PidParameters& params);
	const PidParameters& GetPidParameters(size_t heater) const;
	float TimeToHot() const;
	void SetTimeToHot(float t);
	void SetThermistorNumber(size_t heater, size_t thermistor);
	int GetThermistorNumber(size_t heater) const;
	bool DoThermistorAdc(uint8_t heater) const;
	void SetTemperatureLimit(float t);
	float GetTemperatureLimit() const { return temperatureLimit; }
	static const char* TempErrorStr(TempError err);
	static bool TempErrorPermanent(TempError err);
	void UpdateConfiguredHeaters();

	// Fans

	float GetFanValue(size_t fan) const;					// Result is returned in percent
	void SetFanValue(size_t fan, float speed);				// Accepts values between 0..1 and 1..255
	bool GetCoolingInverted(size_t fan) const;
	void SetCoolingInverted(size_t fan, bool inv);
	float GetFanPwmFrequency(size_t fan) const;
	void SetFanPwmFrequency(size_t fan, float freq);
	float GetTriggerTemperature(size_t fan) const;
	void SetTriggerTemperature(size_t fan, float t);
	uint16_t GetHeatersMonitored(size_t fan) const;
	void SetHeatersMonitored(size_t fan, uint16_t h);
	float GetFanRPM();

	// Flash operations
	void ResetNvData();
	void ReadNvData();
	void WriteNvData();
	void SetAutoSave(bool enabled);

	void UpdateFirmware();

	// AUX device
	void Beep(int freq, int ms);

	// Hotend configuration
	float GetFilamentWidth() const;
	void SetFilamentWidth(float width);
	float GetNozzleDiameter() const;
	void SetNozzleDiameter(float diameter);

	// Fire the inkjet (if any) in the given pattern
	// If there is no inkjet false is returned; if there is one this returns true
	// So you can test for inkjet presence with if(platform->Inkjet(0))

	bool Inkjet(int bitPattern);

	// Direct pin operations
	bool SetPin(int pin, int level);

	// Error logging
	void LogError(ErrorCode e) { errorCodeBits |= (uint32_t)e; }

//-------------------------------------------------------------------------------------------------------
  
private:
	void ResetChannel(size_t chan);					// re-initialise a serial channel

	// These are the structures used to hold out non-volatile data.
	// The SAM3X doesn't have EEPROM so we save the data to flash. This unfortunately means that it gets cleared
	// every time we reprogram the firmware. So there is no need to cater for writing one version of this
	// struct and reading back another.

	struct SoftwareResetData
	{
	  static const uint16_t magicValue = 0x59B2;	// value we use to recognise that all the flash data has been written
	  static const uint32_t nvAddress = 0;			// address in flash where we store the nonvolatile data

	  uint16_t magic;
	  uint16_t resetReason;							// this records why we did a software reset, for diagnostic purposes
	  size_t neverUsedRam;							// the amount of never used RAM at the last abnormal software reset
	};

	struct FlashData
	{
	  static const uint16_t magicValue = 0xA436;	// value we use to recognise that the flash data has been written
	  static const uint32_t nvAddress = SoftwareResetData::nvAddress + sizeof(struct SoftwareResetData);

	  uint16_t magic;

	  // The remaining data could alternatively be saved to SD card.
	  // Note however that if we save them as G codes, we need to provide a way of saving IR and ultrasonic G31 parameters separately.
	  ZProbeParameters switchZProbeParameters;		// Z probe values for the endstop switch
	  ZProbeParameters irZProbeParameters;			// Z probe values for the IR sensor
	  ZProbeParameters alternateZProbeParameters;	// Z probe values for the alternate sensor
	  int zProbeType;								// the type of Z probe we are currently using
	  bool zProbeAxes[AXES];						// Z probe is used for these axes
	  PidParameters pidParams[HEATERS];
	  byte ipAddress[4];
	  byte netMask[4];
	  byte gateWay[4];
	  uint8_t macAddress[6];
	  Compatibility compatibility;
	};

	struct Fan
	{
	  float val;
	  float triggerTemperature;
	  uint16_t freq;
	  uint16_t heatersMonitored;
	  Pin pin;
	  bool inverted;
	  bool hardwareInverted;

	  void Init(Pin p_pin, bool hwInverted);
	  void SetValue(float speed);
	  void SetPwmFrequency(float p_freq);
	  void Refresh();
	  void SetTriggerTemperature(float t) { triggerTemperature = t; }
	  void SetHeatersMonitored(uint16_t h) { heatersMonitored = h; }
	  void Check();
	};

	FlashData nvData;
	bool autoSaveEnabled;

	BoardType board;

	float lastTime;
	float longWait;
	float addToTime;
	unsigned long lastTimeCall;

	bool active;
	uint32_t errorCodeBits;

	void InitialiseInterrupts();
	void GetStackUsage(size_t* currentStack, size_t* maxStack, size_t* neverUsed) const;

	// DRIVES

	void SetSlowestDrive();
	void UpdateMotorCurrent(size_t drive);

	Pin stepPins[DRIVES];							// the Arduino pin numbers for the stepper pins
	OutputPin stepPinDescriptors[DRIVES];			// output pin descriptors for faster access, with the driver number mapping already done
	Pin directionPins[DRIVES];
	Pin enablePins[DRIVES];
	volatile DriveStatus driveState[DRIVES];
	bool directions[DRIVES];
	bool enableValues[DRIVES];
	Pin endStopPins[DRIVES];
	int8_t driverNumbers[DRIVES];
	float maxFeedrates[DRIVES];
	float accelerations[DRIVES];
	float driveStepsPerUnit[DRIVES];
	float instantDvs[DRIVES];
	float elasticComp[DRIVES - AXES];
	float motorCurrents[DRIVES];
	float idleCurrentFactor;
	size_t slowestDrive;

	// Digipots

	MCP4461 mcpDuet;
	MCP4461 mcpExpansion;
	Pin potWipes[8];			// we have only 8 digipots, on the Duet 0.8.5 we use the DAC for the 9th
	float senseResistor;
	float maxStepperDigipotVoltage;
	float maxStepperDACVoltage;

	// Z probe

	Pin zProbePin;
	Pin zProbeModulationPin;
	volatile ZProbeAveragingFilter zProbeOnFilter;					// Z probe readings we took with the IR turned on
	volatile ZProbeAveragingFilter zProbeOffFilter;					// Z probe readings we took with the IR turned off
	volatile ThermistorAveragingFilter thermistorFilters[HEATERS];	// bed and extruder thermistor readings

	float extrusionAncilliaryPWM;

	void InitZProbe();
	uint16_t GetRawZProbeReading() const;
	void UpdateNetworkAddress(byte dst[4], const byte src[4]);

	// Axes and endstops

	float axisMaxima[AXES];
	float axisMinima[AXES];
	EndStopType endStopType[AXES+1];
	bool endStopLogicLevel[AXES+1];
  
  // Heaters - bed is assumed to be the first

	int GetRawTemperature(size_t heater) const;
	void SetHeaterPwm(size_t heater, uint8_t pwm);
	bool AnyHeaterHot(uint16_t heaters, float t) const;				// called to see if we need to turn on the hot end fan

	Pin tempSensePins[HEATERS];
	Pin heatOnPins[HEATERS];
	MAX31855 Max31855Devices[MAX31855_DEVICES];
	Pin max31855CsPins[MAX31855_DEVICES];
	uint32_t configuredHeaters;										// Bitmask of all heaters in use
	float heatSampleTime;
	float timeToHot;
	float temperatureLimit;

	// Fans

	Fan fans[NUM_FANS];
	Pin coolingFanRpmPin;											// we currently support only one fan RPM input
	float lastRpmResetTime;
	void InitFans();

  	// Serial/USB

	uint32_t baudRates[NUM_SERIAL_CHANNELS];
	uint8_t commsParams[NUM_SERIAL_CHANNELS];
	OutputStack *auxOutput;
	OutputStack *aux2Output;
	OutputStack *usbOutput;

	// Files

	MassStorage* massStorage;
	FileStore* files[MAX_FILES];
	bool fileStructureInitialised;
	const char* webDir;
	const char* gcodeDir;
	const char* sysDir;
	const char* macroDir;
	const char* configFile;
	const char* defaultFile;
  
	// Data used by the tick interrupt handler

	// Heater #n, 0 <= n < HEATERS, uses "temperature channel" tc given by
	//
	//     tc = heaterTempChannels[n]
	//
	// Temperature channels follow a convention of
	//
	//     if (0 <= tc < HEATERS) then
	//        The temperature channel is a thermistor read using ADC.
	//        The actual ADC to read for tc is
	//
	//            thermistorAdcChannel[tc]
	//
	//        which, is equivalent to
	//
	//            PinToAdcChannel(tempSensePins[tc])
	//
	//     if (100 <= tc < 100 + (MAX31855_DEVICES - 1)) then
	//        The temperature channel is a thermocouple attached to a MAX31855 chip
	//        The MAX31855 object corresponding to the specific MAX31855 chip is
	//
	//            Max31855Devices[tc - 100]
	//
	//       Note that the MAX31855 objects, although statically declared, are not
	//       initialized until configured via a "M305 Pn X10m" command with 0 <= n < HEATERS
	//       and 0 <= m < MAX31855_DEVICES.
	//
	// NOTE BENE: When a M305 command is processed, the onus is on the gcode processor,
	// GCodes.cpp, to range check the value of the X parameter.  Code consuming the results
	// of the M305 command (e.g., SetThermistorNumber() and array lookups assume range
	// checking has already been performed.

	uint8_t heaterTempChannels[HEATERS];
	adc_channel_num_t thermistorAdcChannels[HEATERS];
	adc_channel_num_t zProbeAdcChannel;
	uint32_t thermistorOverheatSums[HEATERS];
	uint8_t tickState;
	size_t currentHeater;
	int debugCode;

	static uint16_t GetAdcReading(adc_channel_num_t chan);
	static void StartAdcConversion(adc_channel_num_t chan);

	// Hotend configuration
	float filamentWidth;
	float nozzleDiameter;

	// Direct pin manipulation
	static const uint8_t pinAccessAllowed[NUM_PINS_ALLOWED/8];
	uint8_t pinInitialised[NUM_PINS_ALLOWED/8];
};

// Small class to hold an open file and data relating to it.
// This is designed so that files are never left open and we never duplicate a file reference.
class FileData
{
public:
	FileData() : f(NULL) {}

	// Set this to refer to a newly-opened file
	void Set(FileStore* pfile)
	{
		Close();	// close any existing file
		f = pfile;
	}

	bool IsLive() const { return f != NULL; }

	bool Close()
	{
		if (f != NULL)
		{
			bool ok = f->Close();
			f = NULL;
			return ok;
		}
		return false;
	}

	bool Read(char& b)
	{
		return f->Read(b);
	}

	bool Write(char b)
	{
		return f->Write(b);
	}

	bool Write(const char *s, unsigned int len)
	{
		return f->Write(s, len);
	}

	bool Flush()
	{
		return f->Flush();
	}

	FilePosition GetPosition() const
	{
		return f->Position();
	}

	bool Seek(FilePosition position)
	{
		return f->Seek(position);
	}

	float FractionRead() const
	{
		return (f == NULL ? -1.0 : f->FractionRead());
	}

	FilePosition Length() const
	{
		return f->Length();
	}

	// Assignment operator
	void CopyFrom(const FileData& other)
	{
		Close();
		f = other.f;
		if (f != NULL)
		{
			f->Duplicate();
		}
	}

	// Move operator
	void MoveFrom(FileData& other)
	{
		Close();
		f = other.f;
		other.Init();
	}

private:
	FileStore *f;

	void Init()
	{
		f = NULL;
	}

	// Private assignment operator to prevent us assigning these objects
	FileData& operator=(const FileData&);

	// Private copy constructor to prevent us copying these objects
	FileData(const FileData&);
};

// Where the htm etc files are

inline const char* Platform::GetWebDir() const
{
  return webDir;
}

// Where the gcodes are

inline const char* Platform::GetGCodeDir() const
{
  return gcodeDir;
}

// Where the system files are

inline const char* Platform::GetSysDir() const
{
  return sysDir;
}

inline const char* Platform::GetMacroDir() const
{
	return macroDir;
}

inline const char* Platform::GetConfigFile() const
{
  return configFile;
}

inline const char* Platform::GetDefaultFile() const
{
  return defaultFile;
}


//*****************************************************************************************************************

// Drive the RepRap machine - Movement

inline float Platform::DriveStepsPerUnit(size_t drive) const
{
  return driveStepsPerUnit[drive]; 
}

inline void Platform::SetDriveStepsPerUnit(size_t drive, float value)
{
  driveStepsPerUnit[drive] = value;
}

inline float Platform::Acceleration(size_t drive) const
{
	return accelerations[drive];
}

inline const float* Platform::Accelerations() const
{
	return accelerations;
}

inline void Platform::SetAcceleration(size_t drive, float value)
{
	accelerations[drive] = value;
}

inline float Platform::MaxFeedrate(size_t drive) const
{
  return maxFeedrates[drive];
}

inline const float* Platform::MaxFeedrates() const
{
	return maxFeedrates;
}

inline void Platform::SetMaxFeedrate(size_t drive, float value)
{
	maxFeedrates[drive] = value;
}

inline float Platform::ConfiguredInstantDv(size_t drive) const
{
	return instantDvs[drive];
}

inline void Platform::SetInstantDv(size_t drive, float value)
{
	instantDvs[drive] = value;
	SetSlowestDrive();
}

inline size_t Platform::SlowestDrive() const
{
	return slowestDrive;
}

#if 0	// not used
inline const float* Platform::InstantDvs() const
{
	return instantDvs;
}
#endif

inline void Platform::SetDirectionValue(size_t drive, bool dVal)
{
	directions[drive] = dVal;
}

inline bool Platform::GetDirectionValue(size_t drive) const
{
	return directions[drive];
}

inline void Platform::SetEnableValue(size_t drive, bool eVal)
{
	enableValues[drive] = eVal;
}

inline bool Platform::GetEnableValue(size_t drive) const
{
	return enableValues[drive];
}

inline float Platform::AxisMaximum(size_t axis) const
{
	return axisMaxima[axis];
}

inline void Platform::SetAxisMaximum(size_t axis, float value)
{
	axisMaxima[axis] = value;
}

inline float Platform::AxisMinimum(size_t axis) const
{
	return axisMinima[axis];
}

inline void Platform::SetAxisMinimum(size_t axis, float value)
{
	axisMinima[axis] = value;
}

inline float Platform::AxisTotalLength(size_t axis) const
{
	return axisMaxima[axis] - axisMinima[axis];
}

// The A4988 requires 1us minimum pulse width, so we make separate StepHigh and StepLow calls so that we don't waste this time
inline void Platform::StepHigh(size_t drive)
{
	stepPinDescriptors[drive].SetHigh();
}

inline void Platform::StepLow(size_t drive)
{
	stepPinDescriptors[drive].SetLow();
}

inline void Platform::SetExtrusionAncilliaryPWM(float v)
{
	extrusionAncilliaryPWM = v;
}

inline float Platform::GetExtrusionAncilliaryPWM() const
{
	return extrusionAncilliaryPWM;
}

// For the Duet we use the fan output for this
// DC 2015-03-21: To allow users to control the cooling fan via gcodes generated by slic3r etc.,
// only turn the fan on/off if the extruder ancilliary PWM has been set nonzero.
// Caution: this is often called from an ISR, or with interrupts disabled!
inline void Platform::ExtrudeOn()
{
	if (extrusionAncilliaryPWM > 0.0)
	{
		SetFanValue(0,extrusionAncilliaryPWM); //@TODO T3P3 currently only turns fan0 on
	}
}

// DC 2015-03-21: To allow users to control the cooling fan via gcodes generated by slic3r etc.,
// only turn the fan on/off if the extruder ancilliary PWM has been set nonzero.
// Caution: this is often called from an ISR, or with interrupts disabled!
inline void Platform::ExtrudeOff()
{
	if (extrusionAncilliaryPWM > 0.0)
	{
		SetFanValue(0,0.0); //@TODO T3P3 currently only turns fan0 off
	}
}

//********************************************************************************************************

// Drive the RepRap machine - Heat and temperature

inline int Platform::GetRawTemperature(size_t heater) const
{
  return (heater < HEATERS)
		  ? thermistorFilters[heater].GetSum()/(THERMISTOR_AVERAGE_READINGS >> AD_OVERSAMPLE_BITS)
		  : 0;
}

inline float Platform::HeatSampleTime() const
{
  return heatSampleTime;
}

inline void Platform::SetHeatSampleTime(float st)
{
	heatSampleTime = st;
}

inline float Platform::TimeToHot() const
{
	return timeToHot;
}

inline void Platform::SetTimeToHot(float t)
{
	timeToHot = t;
}

inline bool Platform::DoThermistorAdc(uint8_t heater) const
{
	return heaterTempChannels[heater] < HEATERS;
}

// Indicate if a temp sensor error is a "permanent" error: whether it is an
// error condition which will not rectify over time and so the heater should
// just be shut off immediately.
inline bool Platform::TempErrorPermanent(TempError err)
{
	return (err != TempError::errTimeout) && (err != TempError::errIO) && (err != TempError::errOk);
}

inline const uint8_t* Platform::IPAddress() const
{
	return nvData.ipAddress;
}

inline const uint8_t* Platform::NetMask() const
{
	return nvData.netMask;
}

inline const uint8_t* Platform::GateWay() const
{
	return nvData.gateWay;
}

inline const uint8_t* Platform::MACAddress() const
{
	return nvData.macAddress;
}

inline float Platform::GetElasticComp(size_t extruder) const
{
	return (extruder < DRIVES - AXES) ? elasticComp[extruder] : 0.0;
}

inline void Platform::SetEndStopConfiguration(size_t axis, EndStopType esType, bool logicLevel)
//pre(axis < AXES)
{
	endStopType[axis] = esType;
	endStopLogicLevel[axis] = logicLevel;
}

inline void Platform::GetEndStopConfiguration(size_t axis, EndStopType& esType, bool& logicLevel) const
//pre(axis < AXES)
{
	esType = endStopType[axis];
	logicLevel = endStopLogicLevel[axis];
}

// Get the interrupt clock count
/*static*/ inline uint32_t Platform::GetInterruptClocks()
{
	//return TC_ReadCV(TC1, 0);
	// sadly, the Arduino IDE does not provide the inlined version of TC_ReadCV, so use the following instead...
	return TC1 ->TC_CHANNEL[0].TC_CV;
}

// This is called by the tick ISR to get the raw Z probe reading to feed to the filter
inline uint16_t Platform::GetRawZProbeReading() const
{
	if (nvData.zProbeType >= 4)
	{
		bool b = (bool)digitalRead(endStopPins[E0_AXIS]);
		if (!endStopLogicLevel[AXES])
		{
			b = !b;
		}
		return (b) ? 4000 : 0;
	}
	else
	{
		return GetAdcReading(zProbeAdcChannel);
	}
}

inline float Platform::GetFilamentWidth() const
{
	return filamentWidth;
}

inline void Platform::SetFilamentWidth(float width)
{
	filamentWidth = width;
}

inline float Platform::GetNozzleDiameter() const
{
	return nozzleDiameter;
}

inline void Platform::SetNozzleDiameter(float diameter)
{
	nozzleDiameter = diameter;
}

/*static*/ inline void Platform::EnableWatchdog()
{
	const uint32_t wdtTicks = 256;	// number of watchdog ticks @ 32768Hz/128 before the watchdog times out (max 4095)
	WDT_Enable(WDT, (wdtTicks << WDT_MR_WDV_Pos) | (wdtTicks << WDT_MR_WDD_Pos) | WDT_MR_WDRSTEN);	// enable watchdog, reset the mcu if it times out
}

/*static*/ inline void Platform::KickWatchdog()
{
	WDT_Restart(WDT);
}

//***************************************************************************************

#endif