// ATtiny2313, Ext CLK=6MHz
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include <avr/eeprom.h>
#define	C500us	12
#define	LeftHold	0x01				//F:	1:LeftHold
#define	RightHold	0x02				//F:	1:RightHold
#define	SSW			0x10				//F:	Single SW	0:off, 1:on
#define	SW0			0x20				//F:	SW0			0:off, 1:on
#define	SW1			0x40				//F:	SW1			0:off, 1:on
#define	TO			0x80				//F:	TimeOut		0:off, 1:on
prog_uint8_t ctab[]={234,165,117};		// 10ms,7ms,5ms
prog_uint8_t dirtab[]={					// direction
	0<<2,	1<<2,	3<<2,	2<<2,		// R
	0<<4,	1<<4,	3<<4,	2<<4,		// D
	0<<2,	2<<2,	3<<2,	1<<2,		// L
	0<<4,	2<<4,	3<<4,	1<<4		// U
};
uint8_t sw0cntr, sw1cntr, c500us, c10ms, S, F, dir, b;
uint8_t t500us, t10ms, c, m, x, cxms, i, j, u;
SIGNAL(SIG_OVERFLOW0){								// 0.167 * 256 = 42.6666 us
	if(++c10ms>=234){	t10ms++;	c10ms=0;	}	// 10ms sync
	if(++c500us>=C500us){							// 500us sync
		c500us=0;
		if(b>0){	PORTD^=0x40;	b--;	}
		if(bit_is_clear(PINB,0))sw0cntr=100;		// 50ms hold
		else if(sw0cntr>0)		sw0cntr--;
		if(bit_is_clear(PINB,1))sw1cntr=100;		// 50ms hold
		else if(sw1cntr>0)		sw1cntr--;
	}
	if((S==14 || !(F&SSW) && F&SW1) && ++x>=cxms){		// xms sync
		x=0;	u=pgm_read_byte(&dirtab[(uint8_t)(dir+m)]);	m++;	m&=0x03;
		PORTD=u|(PORTD&0x03);
	}
}

int main(void){
	PORTB=0xfc;	DDRB=0x00;					// rrrrrrii
	PORTD=0x03;	DDRD=0x7f;					// xooooooo
	TCNT0=0;	TCCR0B=1;					// TCNT0=0		CLK=0.167 us
	TIMSK=1<<TOIE0;
	sw0cntr=sw1cntr=c=c500us=c10ms=m=x=S=dir=F=0;
	for(i=0;i<255;i++)for(j=0;j<255;j++){}	// ウェイト
	if(eeprom_read_byte(0)>2)	eeprom_write_byte(0,1);
	cxms=pgm_read_byte(&ctab[eeprom_read_byte(0)]);		// 10ms
	if(bit_is_clear(PINB,1))	F|=SSW;		// SW1オンなら1個のSWで操作
	sei();
	for(;;){
		F&=0x1f;
		if(sw0cntr>0)	F|=SW0;
		if(sw1cntr>0)	F|=SW1;
		if(t10ms>=100){	F|=TO;	t10ms=0;	}
		if(S==0){
			if(F&SW0){		S=1;	t10ms=0;	b=100;	}
		}else if(S==1){
			if(F&TO){		S=2;				b=100;	F&=0xfc;}	// Hold off
			else if(!(F&SW0)){
				if(F&SSW){	S=12;	t10ms=0;			}
				else{		S=0;				dir=(dir+4)&0x0c;	}
			}
		}else if(S==2){
			if(F&TO){		S=3;				b=100;	}
			else if(!(F&SW0)){S=5;	t10ms=0;			}
		}else if(S==3){
			if(F&TO){		S=4;				b=100;	}
			else if(!(F&SW0)){S=7;	t10ms=0;			}
		}else if(S==4){
			if(F&TO){		S=15;				b=100;	}
			else if(!(F&SW0)){S=9;	t10ms=0;			}
		}else if(S==5){
			if(F&TO){		S=0;				b=100;	}
			else if(F&SW0){	S=6;	t10ms=0;	b=100;	}
		}else if(S==6){
			if(F&TO){		S=15;				b=100;	F|=LeftHold;}
			else if(!(F&SW0)){S=5;	t10ms=0;			}
		}else if(S==7){
			if(F&TO){		S=0;				b=100;	}
			else if(F&SW0){	S=8;	t10ms=0;	b=100;	}
		}else if(S==8){
			if(!(F&SW0)){	S=7;	t10ms=0;			}
		}else if(S==9){
			if(F&TO){		S=0;				b=100;	}
			else if(F&SW0){	S=10;	t10ms=0;	b=100;	}
		}else if(S==10){
			if(F&TO){		S=11;				b=100;	}
			else if(!(F&SW0)){S=0;	t10ms=0;	eeprom_write_byte(0,0);	cxms=pgm_read_byte(&ctab[0]);}	//低速
		}else if(S==11){
			if(F&TO){		S=15;		b=100;	eeprom_write_byte(0,2);	cxms=pgm_read_byte(&ctab[2]);}	//高速
			else if(!(F&SW0)){S=0;	t10ms=0;	eeprom_write_byte(0,1);	cxms=pgm_read_byte(&ctab[1]);}	//標準
		}else if(S==12){
			if(F&TO){		S=0;				b=100;	}
			else if(F&SW0){	S=13;	t10ms=0;	b=100;	}
		}else if(S==13){
			if(F&TO){		S=14;				b=100;	x=0;}
			else if(!(F&SW0)){S=12;	t10ms=0;	dir=(dir+4)&0x0c;		}
		}else if(S==14){
			if(F&SSW){
				if(!(F&SW0)){S=12;	t10ms=0;			}
			}else{
				if(!(F&SW1))S=0;
			}
		}else if(S==15){
			if(!(F&SW0))	S=0;
		}
		if(S==6 || F&LeftHold)	PORTD&=0xfe;	// LB on
		else 					PORTD|=0x01;	// LB off
		if(S==8)				PORTD&=0xfd;	// RB on
		else					PORTD|=0x02;	// RB off
	}
}