machines/components/pid-controller/firmware/common/Pin.h

#ifndef PIN_H
#define PIN_H

// this class doesn't outperform fastgpio but is works with AtmelMega

#include <Arduino.h>

#define DDR_HIGH (*_DDR |= _offset)	  ///< Set the DDR register to HIGH for the pin
#define DDR_TOGGLE (*_DDR ^= _offset) ///< Set the DDR register to the inverse for the pin
#define DDR_LOW (*_DDR &= _ioffset)	  ///< Set the DDR register to LOW for the pin

#define PORT_HIGH (*_PORT |= _offset)	///< Set the PORT register to HIGH for the pin
#define PORT_TOGGLE (*_PORT ^= _offset) ///< Set the PORT register to the inverse for the pin
#define PORT_LOW (*_PORT &= _ioffset)	///< Set the PORT register to LOW for the pin

#define DDR_ON (*_DDR & _offset)   ///< Get the DDR register for the pin (HIGH, LOW) with other pins forced to 0
#define DDR_OFF (*_DDR | _ioffset) ///< Get the DDR register for the pin (HIGH, LOW) with other pins forced to 1

#define PORT_ON (*_PORT & _offset)	 ///< Get the PORT register for the pin (HIGH, LOW) with other pins forced to 0
#define PORT_OFF (*_PORT | _ioffset) ///< Get the PORT register for the pin (HIGH, LOW) with other pins forced to 1

#define PIN_ON (*_PIN & _offset)   ///< Get the PIN register for the pin (HIGH, LOW) with other pins forced to 0
#define PIN_OFF (*_PIN | _ioffset) ///< Get the PIN register for the pin (HIGH, LOW) with other pins forced to 1

class Pin
{
public:
	Pin(uint8_t number)
	{
		_number = number;
		_offset = digitalPinToBitMask(_number);
		_ioffset = ~_offset;
		_timer = digitalPinToTimer(_number);
		_PIN = portInputRegister(digitalPinToPort(_number));
		_PORT = portOutputRegister(digitalPinToPort(_number));
		_DDR = portModeRegister(digitalPinToPort(_number));
	}

	/**
	Custom board constructor

	getAnalogValue() and setDutyCycle(int value) not supported

	@param number pin number written on board
	@param offset bit mask used to access pin in registers
	@param timer timer for pin
	@param PIN input register for pin
	@param PORT data register for pin
	@param DDR data direction register for pin
	*/
	Pin(uint8_t number, uint8_t offset, uint8_t timer, volatile uint8_t *PIN, volatile uint8_t *PORT, volatile uint8_t *DDR)
	{
		_number = number;
		_offset = offset;
		_ioffset = ~_offset;
		_timer = timer;
		_PIN = PIN;
		_PORT = PORT;
		_DDR = DDR;
	}

	// ################################# Operators #################################

	/**
	Get the value of the pin from the PIN register

	@return true if the value of the pin is HIGH, false otherwise
	*/
	operator bool() const
	{
		return bool(PIN_ON);
	}

	/**
	Set the pin state

	@param state the state of the pin (HIGH, LOW)
	*/
	Pin &operator=(uint8_t state)
	{
		uint8_t oldSREG = SREG;
		cli();
		if (state == LOW)
		{
			PORT_LOW;
		}
		else
		{
			PORT_HIGH;
		}
		SREG = oldSREG;

		return *this;
	}

	// ################################# Getters #################################

	/**
	Get the pin number

	@return pin number
	*/
	uint8_t getNumber()
	{
		return _number;
	}

	/**
	Get the pin offset

	@return pin offset
	*/
	uint8_t getOffset()
	{
		return _offset;
	}

	/**
	Get the inverse pin offset

	@return inverse pin offset
	*/
	uint8_t getInverseOffset()
	{
		return _ioffset;
	}

	/**
	Get the pin timer

	@return pin timer
	*/
	uint8_t getTimer()
	{
		return _timer;
	}

	/**
	Get a pointer to the PIN register

	@return pointer to the PIN register
	*/
	volatile uint8_t *getPIN()
	{
		return _PIN;
	}

	/**
	Get a pointer to the PORT register

	@return pointer to the PORT register
	*/
	volatile uint8_t *getPORT()
	{
		return _PORT;
	}

	/**
	Get a pointer to the DDR register

	@return pointer to the DDR register
	*/
	volatile uint8_t *getDDR()
	{
		return _DDR;
	}

	/**
	Get the mode of the pin from the DDR register

	@return mode of the pin (OUTPUT, INPUT)
	*/
	uint8_t getMode()
	{
		if (DDR_ON)
		{
			return OUTPUT;
		}
		else
		{
			return INPUT;
		}
	}

	/**
	Get the state of the pin from the PORT register

	@return state of the pin (HIGH, LOW)
	*/
	uint8_t getState()
	{
		if (PORT_ON)
		{
			return HIGH;
		}
		else
		{
			return LOW;
		}
	}

	/**
	Get the value of the pin from the PIN register

	@return value of the pin (HIGH, LOW)
	*/
	uint8_t getValue()
	{
		if (PIN_ON)
		{
			return HIGH;
		}
		else
		{
			return LOW;
		}
	}

	/**
	Get the analog value of the pin

	@return analog value of the pin (0-1023)
	*/
	uint16_t getAnalogValue()
	{
		return analogRead(_number);
	}

	/**
	Set the pin mode and pin state

	@param mode the mode of the pin (OUTPUT, INPUT)
	@param state the state of the pin (HIGH, LOW)
	*/
	void set(uint8_t mode, uint8_t state)
	{
		uint8_t oldSREG = SREG;
		cli();
		if (mode == INPUT)
		{
			DDR_LOW;
		}
		else
		{
			DDR_HIGH;
		}
		if (state == LOW)
		{
			PORT_LOW;
		}
		else
		{
			PORT_HIGH;
		}
		SREG = oldSREG;
	}

	/**
	Set the pin mode

	@param mode the mode of the pin (OUTPUT, INPUT)
	*/
	void setMode(uint8_t mode)
	{
		uint8_t oldSREG = SREG;
		cli();
		if (mode == INPUT)
		{
			DDR_LOW;
		}
		else
		{
			DDR_HIGH;
		}
		SREG = oldSREG;
	}

	/**
	Set the pin state

	@param state the state of the pin (HIGH, LOW)
	*/
	void setState(uint8_t state)
	{
		uint8_t oldSREG = SREG;
		cli();
		if (state == LOW)
		{
			PORT_LOW;
		}
		else
		{
			PORT_HIGH;
		}
		SREG = oldSREG;
	}

	// #################### Input ####################

	void setInput()
	{
		uint8_t oldSREG = SREG;
		cli();
		DDR_LOW;
		SREG = oldSREG;
	}

	/**
	Set the pin pullup resistor to on
	*/
	void setPullupOn()
	{
		uint8_t oldSREG = SREG;
		cli();
		PORT_HIGH;
		SREG = oldSREG;
	}

	/**
	Set the pin pullup resistor to off
	*/
	void setPullupOff()
	{
		uint8_t oldSREG = SREG;
		cli();
		PORT_LOW;
		SREG = oldSREG;
	}

	/**
	Set the pin mode to input and the pin pullup resistor to on
	*/
	void setInputPullupOn()
	{
		uint8_t oldSREG = SREG;
		cli();
		DDR_LOW;
		PORT_HIGH;
		SREG = oldSREG;
	}

	/**
	Set the pin mode to input and the pin pullup resistor to off
	*/
	void setInputPullupOff()
	{
		uint8_t oldSREG = SREG;
		cli();
		DDR_LOW;
		PORT_LOW;
		SREG = oldSREG;
	}

	// #################### Output ####################

	/**
	Set the pin mode to output
	*/
	void setOutput()
	{
		uint8_t oldSREG = SREG;
		cli();
		DDR_HIGH;
		SREG = oldSREG;
	}

	/**
	Set the pin output to HIGH
	*/
	void setHigh()
	{
		uint8_t oldSREG = SREG;
		cli();
		PORT_HIGH;
		SREG = oldSREG;
	}

	/**
	Set the pin output to LOW
	*/
	void setLow()
	{
		uint8_t oldSREG = SREG;
		cli();
		PORT_LOW;
		SREG = oldSREG;
	}

	/**
	Set the pin mode to output and the pin output to HIGH
	*/
	void setOutputHigh()
	{
		uint8_t oldSREG = SREG;
		cli();
		DDR_HIGH;
		PORT_HIGH;
		SREG = oldSREG;
	}

	/**
	Set the pin mode to output and the pin output to LOW
	*/
	void setOutputLow()
	{
		uint8_t oldSREG = SREG;
		cli();
		DDR_HIGH;
		PORT_LOW;
		SREG = oldSREG;
	}

	/**
	Set the PWM duty cycle

	@param value the duty cycle (0-255)
	*/
	void setDutyCycle(int value)
	{
		analogWrite(_number, value);
	}

	// ################################# Utilities #################################

	/**
	Toggle the pin mode (OUTPUT -> INPUT, INPUT -> OUTPUT)
	*/
	void toggleMode()
	{
		uint8_t oldSREG = SREG;
		cli();
		DDR_TOGGLE;
		SREG = oldSREG;
	}

	/**
	Toggle the pin state (HIGH -> LOW, LOW -> HIGH)
	*/
	void toggleState()
	{
		uint8_t oldSREG = SREG;
		cli();
		PORT_TOGGLE;
		SREG = oldSREG;
	}

	// #################### RC Timer ####################

	/**
	Set the pin mode to input and decrement a counter until the pin goes HIGH or the counter reaches 0 then set the pin mode to output and return the counter value

	@param count the initial value for the counter to start at (0-65535)

	@return the value remaining on the counter when the pin state went to HIGH or 0 if the counter reached 0
	*/
	volatile unsigned int rcTimer(volatile unsigned int count)
	{
		uint8_t status;
		asm volatile(
			// Save interupt status and disable interupts
			"in %[status], __SREG__ \n\t" // Store current interupt status in variable 's'
			"cli \n\t"					  // Disable interupts

			// Set Pin to input mode to start charging capacitor
			"ld __tmp_reg__, %a[_DDR] \n\t"		// Load the DDR register into r0 (__tmp_reg__)
			"and __tmp_reg__, %[_ioffset] \n\t" // Apply the bit mask (offset) to r0 (__tmp_reg__)
			"st %a[_DDR], __tmp_reg__ \n\t"		// Store r0 (__tmp_reg__) in the DDR register

			// Count time before Pin becomes high
			"loop%=: \n\t" // Label for looping
			//"ld __tmp_reg__,%a[_PIN] \n\t"   // Load the PIN register into r0 (__tmp_reg__)
			"and __tmp_reg__, %[_offset] \n\t" // Apply the bit mask (offset) to r0 (__tmp_reg__)
			"brne end%= \n\t"				   // End the loop if r0 (__tmp_reg__) is not equal to zero by branching to label 'end'
			"dec %[count] \n\t"				   // Decrement the value of 'count' by one
			"brne loop%= \n\t"				   // If the value of 'count' is not equal to zero continue the loop by branching to label 'loop'

			// Done counting
			"end%=: \n\t" // Label for ending loop
			// Set Pin to output mode to start discharging capacitor
			"ld __tmp_reg__, %a[_DDR] \n\t"	  // Load the DDR register into r0 (__tmp_reg__)
			"or __tmp_reg__, %[_offset] \n\t" // Apply the bit mask (offset) to r0 (__tmp_reg__)
			"st %a[_DDR], __tmp_reg__ \n\t"	  // Store r0 (__tmp_reg__) in the PORT register

			// Restore interupt status
			"out __SREG__, %[status] \n\t" // Load interupt status from variable 's'

			// Outputs
			:
			[ count ] "+r"(count),	 // The value the counter was at when the pin went high
			[ status ] "=&r"(status) // The interupt status

			// Inputs
			:
			[ _DDR ] "e"(_DDR),		   // The address of the DDR register for the pin
			[ _PIN ] "e"(_PIN),		   // The address of the PIN register for the pin
			[ _offset ] "r"(_offset),  // The bit mask used to access pin in registers
			[ _ioffset ] "r"(_ioffset) // The inverse bit mask used to access pin in registers
		);

		return count;
	}

private:
	uint8_t _number;
	uint8_t _offset;
	uint8_t _ioffset;
	uint8_t _timer;
	volatile uint8_t *_PIN;
	volatile uint8_t *_PORT;
	volatile uint8_t *_DDR;
};
#endif