// Arduino G-code Interpreter
// v1.0 by Mike Ellery - initial software (mellery@gmail.com)
// v1.1 by Zach Smith - cleaned up and did lots of tweaks (hoeken@gmail.com)
// v1.2 by Chris Meighan - cleanup / G2&G3 support (cmeighan@gmail.com)
// v1.3 by Zach Smith - added thermocouple support and multi-sample temp readings. (hoeken@gmail.com)
//      also added preliminary and experimental support for rotary encoders.

#include <HardwareSerial.h>

//our command string
#define COMMAND_SIZE 128
char word[COMMAND_SIZE];
byte serial_count;
int no_data = 0;

void setup()
{
	//Do startup stuff here
	Serial.begin(19200);
	Serial.println("start");
	Serial.println("v1.3");
	
	//other initialization.
	init_process_string();
	init_steppers();
	init_extruder();
}

void loop()
{
	char c;
	
	//keep it hot!
	extruder_manage_temperature();

	//read in characters if we got them.
	if (Serial.available() > 0)
	{
		c = Serial.read();
		no_data = 0;
		
		//newlines are ends of commands.
		if (c != '\n')
		{
			word[serial_count] = c;
			serial_count++;
		}
	}
	//mark no data.
	else
	{
		no_data++;
		delayMicrosecondsInterruptible(100);
	}

	//if theres a pause or we got a real command, do it
	if (serial_count && (c == '\n' || no_data > 100))
	{
		//process our command!
		process_string(word, serial_count);

		//clear command.
		init_process_string();
	}

	//no data?  turn off steppers
	if (no_data > 1000)
		disable_steppers();
}

void delayMicrosecondsInterruptible(unsigned int us)
{

#if F_CPU >= 16000000L
    // for the 16 MHz clock on most Arduino boards

	// for a one-microsecond delay, simply return.  the overhead
	// of the function call yields a delay of approximately 1 1/8 us.
	if (--us == 0)
		return;

	// the following loop takes a quarter of a microsecond (4 cycles)
	// per iteration, so execute it four times for each microsecond of
	// delay requested.
	us <<= 2;

	// account for the time taken in the preceeding commands.
	us -= 2;
#else
    // for the 8 MHz internal clock on the ATmega168

    // for a one- or two-microsecond delay, simply return.  the overhead of
    // the function calls takes more than two microseconds.  can't just
    // subtract two, since us is unsigned; we'd overflow.
	if (--us == 0)
		return;
	if (--us == 0)
		return;

	// the following loop takes half of a microsecond (4 cycles)
	// per iteration, so execute it twice for each microsecond of
	// delay requested.
	us <<= 1;
    
    // partially compensate for the time taken by the preceeding commands.
    // we can't subtract any more than this or we'd overflow w/ small delays.
    us--;
#endif

	// busy wait
	__asm__ __volatile__ (
		"1: sbiw %0,1" "\n\t" // 2 cycles
		"brne 1b" : "=w" (us) : "0" (us) // 2 cycles
	);
}