/* 4*4 MATRIX */

#include <stdlib.h>
#include <avr/io.h>
#include <avr/signal.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>


#define XTAL 1000000L
#define REFRESH 100
#define PRESCALE 256
#define RELOAD (0xff-(XTAL/(REFRESH*4)/PRESCALE))

#define MAXCOL 4
#define MAXROW 4

#define COLPORT PORTD
#define COLDDR  DDRD

#define ROWPORT PORTC
#define ROWDDR  DDRC

#define L0000 0x00
#define L0001 0x01
#define L0010 0x02
#define L0011 0x03
#define L0100 0x04
#define L0101 0x05
#define L0110 0x06
#define L0111 0x07
#define L1000 0x08
#define L1001 0x09
#define L1010 0x0a
#define L1011 0x0b
#define L1100 0x0c
#define L1101 0x0d
#define L1110 0x0e
#define L1111 0x0f

#define ENDSEQ 0
#define DELAY0 20
#define DELAY1 50
#define DELAY2 100
#define DELAY3 200

const unsigned char updo[] PROGMEM = { // lines up down
	DELAY2,L0001,L0001,L0001,L0001, // up
	DELAY2,L0010,L0010,L0010,L0010,
	DELAY2,L0100,L0100,L0100,L0100,
	DELAY2,L1000,L1000,L1000,L1000,
	DELAY2,L0100,L0100,L0100,L0100, // down
	DELAY2,L0010,L0010,L0010,L0010,
	DELAY2,L0001,L0001,L0001,L0001, 
	ENDSEQ
};

const unsigned char leri[] PROGMEM = { // lines left right
	DELAY2,L1111,L0000,L0000,L0000, 
	DELAY2,L0000,L1111,L0000,L0000,
	DELAY2,L0000,L0000,L1111,L0000,
	DELAY2,L0000,L0000,L0000,L1111,
	DELAY2,L0000,L0000,L1111,L0000, 
	DELAY2,L0000,L1111,L0000,L0000,
	DELAY2,L1111,L0000,L0000,L0000, 
	ENDSEQ
};

const unsigned char redblink[] PROGMEM = { 
	DELAY2,L1010,L0101,L1010,L0101, 
	DELAY2,L0000,L0000,L0000,L0000,
	ENDSEQ
};

const unsigned char yellowblink[] PROGMEM = { 
	DELAY2,L0101,L1010,L0101,L1010, 
	DELAY2,L0000,L0000,L0000,L0000,
	ENDSEQ
};

const unsigned char twist[] PROGMEM = { 
	DELAY0,L1000,L0000,L0000,L0000, 
	DELAY0,L0000,L1000,L0000,L0000,
	DELAY0,L0000,L0000,L1000,L0000,
	DELAY0,L0000,L0000,L0000,L1000,
	
	DELAY0,L0000,L0000,L0000,L0100,
	DELAY0,L0000,L0000,L0000,L0010,
	DELAY0,L0000,L0000,L0000,L0001,
	
	DELAY0,L0000,L0000,L0001,L0000,
	DELAY0,L0000,L0001,L0000,L0000,
	DELAY0,L0001,L0000,L0000,L0000,
	
	DELAY0,L0010,L0000,L0000,L0000,
	DELAY0,L0100,L0000,L0000,L0000,
	DELAY0,L0000,L0100,L0000,L0000,
	DELAY0,L0000,L0000,L0100,L0000,
	DELAY0,L0000,L0000,L0010,L0000,
	DELAY0,L0000,L0010,L0000,L0000,
	ENDSEQ
};

#define MAXSEQ 5

const unsigned char *sequences[] PROGMEM ={updo,leri,redblink,
	yellowblink,twist};

volatile unsigned char col[MAXCOL];
// unsigned char colbuffer[MAXCOL];

volatile unsigned char actcol;

SIGNAL(SIG_OVERFLOW0)
{
	TCNT0=RELOAD;
	if (actcol<MAXCOL-1) actcol++;
	else actcol=0;
	// colbuffer[actcol]=col[actcol];
	ROWPORT=col[actcol];
	COLPORT=(1<<actcol);
}


void init_timer1(void)
{
	TCCR0=(1<<CS02); // Prescale 256
	TCNT0=RELOAD;
	TIMSK|=(1<<TOIE0);
}


void random_seeding(void)
{
	// read input ADC4 (PC4) as random seed
	DDRC&=~(1<<DDC4);	// PC4 as input
	ADMUX=(1<<REFS1)|(1<<REFS0)|(1<<MUX2);
	ADCSRA=(1<<ADEN)|(1<<ADSC);
	while (ADCSRA&(1<<ADSC));
	srand(ADC);
	ADCSRA=0;
}

void delay(unsigned int d)
{
	int i,j;
	
	for (i=0;i<1000;i++) 
		for (j=0;j<d;j++) asm volatile ("NOP");
}

void random_seq(void)
{
	int num=0;
	unsigned char rrow,rcol;
	
	do {
		rrow=(unsigned char)((rand()&0xff)*MAXCOL/0xff);
		rcol=(unsigned char)((rand()&0xff)*MAXCOL/0xff);
		col[rcol]^=(1<<rrow);
		delay(DELAY2);
		num++;
	} while(num<20);
}

void play_sequence(unsigned char num)
{
	unsigned char bwait;
	unsigned int i=0,j;
	PGM_VOID_P pseq;
	
	pseq=(PGM_VOID_P)pgm_read_word(&sequences[num]);
	
	while(1) {
		bwait=pgm_read_byte(pseq+i);
		if (bwait==ENDSEQ) return;
		i++;
		for (j=0;j<MAXCOL;j++) {
			col[j]=pgm_read_byte(pseq+i);
			i++;
		}
		delay(bwait);
	}
}

int main(void)
{
	int i;
	unsigned char actseq;
	
	ROWDDR=0xff;
	COLDDR=0xff;
	
	for (i=0;i<MAXCOL;i++) col[i]=0; // (1<<i);
	
	actcol=1;
	
	random_seeding();

	init_timer1();
	sei();
	
	while(1) {
		actseq=(unsigned char)((rand()&0xff)*(MAXSEQ+1)/0xff);
		if (actseq>=MAXSEQ) random_seq();
		else play_sequence(actseq);
	}
	
	return 0;
}