#include <pic.h>

/*

 IR send program

 read volume -> send volume value by IR of NEC format
 
 use PIC12F683
 	osc		internal 2MHz
 	PWM		IR carrier frequency(38kHz D=1/3)
 	TMR0		IR ON/OFF time(0.56ms)
 	TMR1		10ms count
	A/D		volume data
 	SLEEP
 
 pin assign
	GP2: IR signal
	GP3: send button(interrupt)
	GP4: volume(A/D)
	GP5: volume bias pin

 action
 	button on			-> read volume & send volume value(1byte) by IR
 	continue button on	-> repeat        send volume value(1byte) by IR
 	button off		-> sleep mode

 NEC format(http://www.necel.com/faq/ja/mi_com/f_com_remo.html)
 	carrier frequency 38kHz(D=1/3)
	 	reader code	1bit		   on 9.0ms  off 4.5ms
 		custom code	2byte	1: on 0.56ms off 0.56ms		0: on 0.56ms off 1.68ms
		data   code	1byte	1: on 0.56ms off 0.56ms		0: on 0.56ms off 1.68ms
		^data  code	1byte	1: on 0.56ms off 0.56ms		0: on 0.56ms off 1.68ms
		stop   code	1bit		   on 0.56ms off ?ms
	total 108ms
	1cycle send 1byte

*/

__CONFIG(
//		FCMEN	&
//		IESOEN	&
		BORDIS	&
		UNPROTECT	&
		MCLRDIS	&
		PWRTDIS	&
		WDTDIS	&
//		INTCLK
		INTIO
		);

#define	READER_ON		(255 - 138)			// 9.0ms		TMR0 1:32
#define	READER_OFF	(255 -  68)			// 4.5ms		TMR0 1:32
#define	DATA_ON		(255 -  60)			// 0.56ms		TMR0 1:4
#define	DATA_OFF		(255 -  44)			// 0.56ms		TMR0 1:4
#define	DATA_OFF_3	(255 - 182)			// 0.56ms * 3	TMR0 1:4
#define	TMR1_10MS		((0xffff - 5000)>>8)	// 10ms TMR1 use high byte
#define	BUF_SIZE		5					// 4byte( custom + custom + data + ~data) + 1byte(stop)
#define	REPEAT_PERIOD	20					// ir_send() repeat each 10ms * X in button on
#define	CNT_SLEEP		100					// time untill sleep mode : 10ms * X (X > 15)
#define	CUSTOM_CODE_1	0x86
#define	CUSTOM_CODE_2	0x23
//#define	IR_OUT		GPIO5
#define	VOLUM_TRIS	TRISIO5
#define	VOLUM_IO		GPIO5
#define	BUTTON		GPIO3
#define	pwm_start()	{ T2CON,TMR2ON = 1; TRISIO2 = 0; }
#define	pwm_stop()	{ T2CON,TMR2ON = 0; TRISIO2 = 1; }
#define	tmr0_start()	{ INTCON,T0IF  = 0; INTCON,T0IE = 1; }
#define	tmr0_stop()	{ INTCON,T0IF  = 0; INTCON,T0IE = 0; }
#define	tmr1_start()	{ PIR1,TMR1IF  = 0; PIE1,TMR1IE = 1; T1CON,TMR1ON = 1; }
#define	tmr1_stop()	{ PIR1,TMR1IF  = 0; PIE1,TMR1IE = 0; T1CON,TMR1ON = 0; }

unsigned char cnt_bit  = 0;						// ir buffer index (unit:bit)
unsigned char ir_buf_i = 0;						// ir buffer index (unit:byte)
unsigned char ir_buf[BUF_SIZE];					// ir data buffer
volatile unsigned char burst = 0;					// 1:burst		0:off
volatile unsigned char reader = 0;				// 1:reader code	0:data code
volatile unsigned char ir_buf_full = 0;			// 1:data sending	0:idle
volatile unsigned char flg_button  = 0;			// 1:button on	0:button off
volatile unsigned char flg_10ms    = 0;			// 1:10ms cnt		0:not yes 10ms

void init();										// initial setup
unsigned char func(unsigned char cnt, char *p);	// read A/D & count up 10ms at button on
void pwm_init();									// pwm setup
char ir_set_char(unsigned char c);					// ir set charactor
void ir_send(unsigned char c);					// ir data send by NEC format
void adc_init();									// A/D setup
unsigned char adc_read(unsigned char ch);			// read A/D of ch

void interrupt interrupt_func()
{
	unsigned char 	c;
	unsigned char	i;
	
	/* TMR0(IR send) */
	if(INTCON,T0IF ==1){
		INTCON,T0IF = 0;
		if(ir_buf_full == 0){		// already finished sending & other interrupt -> jump to ir send routine
			goto IR_SEND_END;
		}	
		
		/* reader code */
		if(reader == 1){
			if(burst == 1){
				TMR0 = READER_OFF;
				pwm_stop();
				burst = 0;
			}else{
				burst = 1;
				
				OPTION = 0x01;	//	TMR0 1:4
				TMR0 = DATA_ON;
				reader = 0;		// reader code finish
				pwm_start();
			}
			
		/* data code */	
		} else {
			if(burst == 1){
				pwm_stop();
				burst = 0;
				i = cnt_bit >> 3;			// ir_buf index is calucurated by cnt_bit / 8
				c = ir_buf[i];	
				TMR0 = (c & 0x01) ? DATA_OFF_3 : DATA_OFF;
				ir_buf[i] = c >> 1;
				cnt_bit++;
			} else {
				if(cnt_bit == (32+1)){			// include stop bit
					cnt_bit = 0;
					ir_buf_full = 0;
					tmr0_stop();
					goto IR_SEND_END;
				}
				pwm_start();
				burst = 1;
				TMR0 = DATA_ON;
			}
		}
	}
IR_SEND_END:
	
	/* GPIO(GPIO3 @ button) */
	if(INTCON,GPIF == 1){
		INTCON,GPIF = 0;
		if(BUTTON == 0){
			flg_button = 1;
		}else{
			flg_button = 0;
		}
	}
	/* TMR1 @ 10ms */
	if(PIR1,TMR1IF == 1){
		PIR1,TMR1IF = 0;
		TMR1H = TMR1_10MS;
		flg_10ms = 1;
	}
	
}	

void init()
{
	OSCTUNE = 0x01;
	OSCCON  = 0x57;		//	f=2MHz
	
	TRISIO  = 0b11011011;
	CMCON0  = 0x07;		// comparator off
	WPU     = 0b11011011;	// ir out pin & volume out pin not pull up

	INTCON  = 0xc8;		// GPIE interrupt on
	OPTION  = 0x01;		// TMR0 1:4
	IOC     = 0x08;		// GP3 enable interrupt-on-change
	TMR0    = DATA_OFF;
	
	T1CON   = 0x00;
	TMR1H   = TMR1_10MS;
	
	// PWM setup
	pwm_init();
	
	// A/D setup
	adc_init();
	
}	

unsigned char func(unsigned char cnt, char *p)
{
	if(BUTTON == 0){
		*(p + (cnt & 0x03)) = adc_read(3);
		cnt++;
	}else{
		cnt = 0;
//		tmr1_stop();
	}
	
	return cnt;
}
	
main()
{
	unsigned char	ad[4];
	unsigned char	cnt10ms = 0;
	unsigned char	cnt_slp = 0;
	unsigned int		sum 	   = 0;
	
	init();	

	tmr1_start();
	while(1)
	{
		if(flg_10ms == 1){
			flg_10ms = 0;
			cnt10ms = func(cnt10ms, ad);	// read A/D & remove chattering
			if(cnt10ms == 0){				// button off
				cnt_slp++;
			}else if(cnt10ms == 4){
				if(ir_buf_full == 0){
					sum = ad[0] + ad[1] + ad[2] + ad[3];
					ir_send(sum >> 2);		// send IR data of A/D
//					ir_send(0x00);		
				}
			}
		}	

		if(cnt10ms == REPEAT_PERIOD){		// ir_send() at 10ms * N period
			cnt10ms = 0;
		}

		if(cnt_slp == CNT_SLEEP){
			cnt_slp = 0;
			tmr1_stop();
			VOLUM_TRIS = 1;				// save volume current
			asm("sleep");
		}	

		if(flg_button == 1){				// almost sleep wake up
			flg_button = 0;
			
			/* set up */
			tmr1_start();
			VOLUM_TRIS = 0;
			VOLUM_IO   = 1;
			cnt10ms    = 0;
			cnt_slp    = 0;
			cnt10ms    = func(cnt10ms, ad);
		}
	}

}


void pwm_init()
{
	// f=38kHz D=1/3
	CCP1CON = 0x1c;	
	CCPR1L  = 0x04;
	PR2     = 0x0c;
	T2CON   = 0x00;
}	



char ir_set_char(unsigned char c)
{
	if((ir_buf_i >= BUF_SIZE)){
		return 0;
	} else {
		ir_buf[ir_buf_i++] = c;
		return 1;
	}
}
	
void ir_send(unsigned char c)
{
	unsigned char	i, j;
	
	ir_buf_full = 1;
	
	/* clear ir buffer */
	for(i=0; i<BUF_SIZE; i++){
		ir_buf[i] = 0;
	}
	ir_buf_i = 0;
	
	/* set data */
	ir_set_char(CUSTOM_CODE_1);
	ir_set_char(CUSTOM_CODE_2);
	ir_set_char(c);
	ir_set_char(~c);

	/* setup reader code */
	OPTION = 0x04;	//	TMR0 1:32 for reader code
	pwm_start();
	TMR0   = READER_ON;
	burst  = 1;
	reader = 1;	
	tmr0_start();
}

void adc_init()
{
	ADCON0 = 0x00;
	ANSEL  = 0b01001000;	// Fosc/4 A/Dch ANS3
}	

unsigned char adc_read(unsigned char ch)
{
	ch     = ch & 0x03;
	ADCON0 = (ADCON0 & 0xf3) | (ch << 2);	// select ch
	ADON   = 1;
	GODONE = 1;
	while(GODONE){
		;
	}
	ADON   = 0;
	return ADRESH;
}