/*
------------------------------------------------------------------------
File    : NoiseRaw.c
Project : Gentrop
Version : 1.0.0
Author  : GioDim
Comment : Arduino sketch
History :
24.02.2018 - Release 1.0.0
------------------------------------------------------------------------
Copyleft 2018 GioDim <giodim@autistici.org>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
	
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
------------------------------------------------------------------------
*/

/*
------------------------------------------------------------------------
Define
------------------------------------------------------------------------
*/

# define	NOISE_PIN		7
# define	BUF_LEN			256
# define	DELAY			2
# define	BAUD_RATE		115200
# define	NUM_BITS		8

# define	FIRST_BIT		0
# define	SECOND_BIT		1

/*
------------------------------------------------------------------------
Global
------------------------------------------------------------------------
*/

int
	Status  = FIRST_BIT,
	Noise   = 0,
	Noise_A = 0,
	Noise_B = 0,
	Bits    = 0,
	Line    = 0;

uint8_t 
	Result = 0,
	Buf [BUF_LEN];
 
/*
------------------------------------------------------------------------
Function : setup
Input    :
Output   :
Comment  :
------------------------------------------------------------------------
*/

void setup ()
{

	pinMode (NOISE_PIN, INPUT);

	Serial.begin (BAUD_RATE);

	for (int  i = 0; i < BUF_LEN; i++)
		Buf [i] = 0;

}

/*
------------------------------------------------------------------------
Function : loop
Input    :
Output   :
Comment  :
------------------------------------------------------------------------
*/

void loop ()
{

	uint8_t
		pause = 0;
	int
		i = 0,
		j = 0;

	// Read noise bit

	Noise = digitalRead (NOISE_PIN);

	if (Status == FIRST_BIT)
	{

		// First bit

		Noise_A = Noise;
		Status  = SECOND_BIT;

	}
	else
	{

		// Second bit

		Noise_B = Noise;
		Status  = FIRST_BIT;

		// Skip if bits are equal

		if (Noise_A != Noise_B)
		{

			// Store bit in byte

			Result <<= 1;
			Result  |= Noise_A;

			if (++Bits == NUM_BITS)
			{

				// Store byte in buffer

				Buf [Line++] = Result;

				if (Line == BUF_LEN)
				{

					// Send buffer

					Serial.write (Buf, BUF_LEN);
					Line = 0;

				}

				Result = 0;
				Bits   = 0;

			}

		}

	}

	// Delay loops

	for (i = 0; i < DELAY; i++)
		for (j = 0; j < DELAY; j++)
			pause++;

}