/*----------------------------------------------------------------------------/
/  8-pin SD audio player R0.05c                    (C)ChaN, 2011              /
/-----------------------------------------------------------------------------/
/ This project, program codes and circuit diagrams, is opened under license
/ policy of following trems.
/
/  Copyright (C) 2010, ChaN, all right reserved.
/
/ * This project is a free software and there is NO WARRANTY.
/ * No restriction on use. You can use, modify and redistribute it for
/   personal, non-profit or commercial use UNDER YOUR RESPONSIBILITY.
/ * Redistributions of source code must retain the above copyright notice.
/
/----------------------------------------------------------------------------*/

#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <avr/wdt.h>
#include <string.h>
#include "pff.h"

#ifndef MODE
#error Wrong make file.
#endif

/* This is the fuse settings for each operating mode. The fuse data will be
   included in the output hex file with program code. However some flash programmers
   may not support this sort of hex files. If it is the case, use these values to
   program the fuse bits.
*/
#if   MODE == 0
FUSES = {0xE1, 0xDD, 0xFF};	/* Mono: Low, High and Extended */
#elif MODE >= 1
FUSES = {0xE1, 0x7D, 0xFF};	/* Stereo and Mono-HR: Low, High and Extended (*HVS mode only*) */
#endif


#define FCC(c1,c2,c3,c4)	(((DWORD)c4<<24)+((DWORD)c3<<16)+((WORD)c2<<8)+(BYTE)c1)	/* FourCC */

void delay_ms (WORD);	/* Defined in asmfunc.S */
void delay_us (WORD);	/* Defined in asmfunc.S */



/*---------------------------------------------------------*/
/* Work Area                                               */
/*---------------------------------------------------------*/

volatile BYTE FifoRi, FifoWi, FifoCt;	/* FIFO controls */

BYTE Buff[256];		/* Wave output FIFO */

FATFS Fs;			/* File system object */
DIR Dir;			/* Directory object */
FILINFO Fno;		/* File information */

WORD rb;			/* Return value. Put this here to avoid avr-gcc's bug */



/*---------------------------------------------------------*/

static
DWORD load_header (void)	/* 0:Invalid format, 1:I/O error, >=1024:Number of samples */
{
	DWORD sz, f;
	BYTE b, al = 0;


	if (pf_read(Buff, 12, &rb)) return 1;	/* Load file header (12 bytes) */

	if (rb != 12 || LD_DWORD(Buff+8) != FCC('W','A','V','E')) return 0;

	for (;;) {
		wdt_reset();
		pf_read(Buff, 8, &rb);			/* Get Chunk ID and size */
		if (rb != 8) return 0;
		sz = LD_DWORD(&Buff[4]);		/* Chunk size */

		switch (LD_DWORD(&Buff[0])) {	/* FCC */
		case FCC('f','m','t',' ') :					/* 'fmt ' chunk */
			if (sz & 1) sz++;						/* Align chunk size */
			if (sz > 100 || sz < 16) return 0;		/* Check chunk size */
			pf_read(Buff, sz, &rb);					/* Get content */
			if (rb != sz) return 0;
			if (Buff[0] != 1) return 0;				/* Check coding type (LPCM) */
			b = Buff[2];
			if (b != 1 && b != 2) return 0;			/* Check channels (1/2) */
			GPIOR0 = al = b;						/* Save channel flag */
			b = Buff[14];
			if (b != 8 && b != 16) return 0;		/* Check resolution (8/16 bit) */
			GPIOR0 |= b;							/* Save resolution flag */
			if (b & 16) al <<= 1;
			f = LD_DWORD(&Buff[4]);					/* Check sampling freqency (8k-48k) */
			if (f < 8000 || f > 48000) return 4;
			OCR0A = (BYTE)(F_CPU / 8 / f) - 1;		/* Sampling freq */
			break;

		case FCC('d','a','t','a') :		/* 'data' chunk */
			if (!al) return 0;							/* Check if format valid */
			if (sz < 1024 || (sz & (al - 1))) return 0;	/* Check size */
			if (Fs.fptr & (al - 1)) return 0;			/* Check offset */
			return sz;									/* Start to play */

		case FCC('D','I','S','P') :		/* 'DISP' chunk */
		case FCC('L','I','S','T') :		/* 'LIST' chunk */
		case FCC('f','a','c','t') :		/* 'fact' chunk */
			if (sz & 1) sz++;				/* Align chunk size */
			pf_lseek(Fs.fptr + sz);			/* Skip this chunk */
			break;

		default :						/* Unknown chunk */
			return 0;
		}
	}

	return 0;
}



static
void ramp (
	int dir		/* 0:Ramp-down, 1:Ramp-up */
)
{
	BYTE v, d, n;


	if (dir) {
		v = 0; d = 1;
	} else {
		v = 128; d = (BYTE)-1;
	}

	n = 128;
	do {
		v += d;
		OCR1A = v; OCR1B = v;
		delay_us(100);
	} while (--n);
}



static
FRESULT play (
	const char *dir,	/* Directory */
	const char *fn		/* File */
)
{
	DWORD sz;
	FRESULT res;
	BYTE sw;
	WORD btr;


	strcpy((char*)Buff, dir);	/* sprintf(Buff, "%s/%s", dir, fn); */
	strcat((char*)Buff, "/");
	strcat((char*)Buff, fn);

	wdt_reset();
	res = pf_open((char*)Buff);		/* Open sound file */
	if (res == FR_OK) {
		sz = load_header();			/* Check file format and ready to play */
		if (sz < 1024) return 255;	/* Cannot play this file */

		if (!TCCR1) {				/* Enable audio out if not enabled */
			PLLCSR = 0b00000110;	/* Select PLL clock for TC1.ck */
			GTCCR =  0b01100000;	/* Enable TC1.OCB as PWM out (L-ch) */
			TCCR1 = MODE ? 0b01100001 : 0b00000001;	/* Start TC1 with TC1.OCA is enabled as PWM out (R-ch) */
			TCCR0A = 0b00000010;	/* Enable TC0.ck = 2MHz as interval timer */
			TCCR0B = 0b00000010;
			TIMSK = _BV(OCIE0A);
			ramp(1);
		}

		FifoCt = 0; FifoRi = 0; FifoWi = 0;		/* Reset FIFO */
		pf_read(0, 512 - (Fs.fptr % 512), &rb);	/* Snip sector unaligned part */
		sz -= rb;

		sw = 1;		/* Button status flag */
		do {
			wdt_reset();
			/* Forward audio data */
			btr = (sz > 1024) ? 1024 : (WORD)sz;/* A chunk of audio data */
			res = pf_read(0, btr, &rb);			/* Forward the data into audio FIFO */
			if (res != FR_OK || btr != rb) break;
			sz -= rb;
			/* Check button down and break on button down */
			sw <<= 1;
			if (bit_is_clear(PINB, 0) && ++sw == 1) break;
		} while (rb == 1024);	/* Repeat until all data forwarded */
	}

	while (FifoCt) ;			/* Wait for audio FIFO empty */
	OCR1A = 128; OCR1B = 128;	/* Return output to center */

	return res;
}



static
void delay500 (void)
{
	wdt_reset();
	TCCR0B = 0; TCCR0A = 0;	/* Stop TC0 */

	if (TCCR1) {
		ramp(0);
		TCCR1 = 0; GTCCR = 0;	/* Stop TC1 */
	}

	WDTCR = _BV(WDE) | _BV(WDIE) | 0b101;	/* Enable WDT interrupt in timeout of 0.5s */
	set_sleep_mode(SLEEP_MODE_PWR_DOWN);	/* Enter power down mode */
	sleep_mode();

	wdt_reset();
	WDTCR = _BV(WDE) | 0b110;				/* Enable WDT reset in timeout of 1s */
}

EMPTY_INTERRUPT(WDT_vect);



/*-----------------------------------------------------------------------*/
/* Main                                                                  */


int main (void)
{
	FRESULT res;
	char *dir;
	BYTE org_osc = OSCCAL;


	MCUSR = 0;
	WDTCR = _BV(WDE) | 0b110;	/* Enable WDT reset in timeout of 1s */

	PORTB = 0b101001;		/* Initialize port: - - H L H L L P */
	DDRB  = 0b111110;

	sei();

	for (;;) {
		if (pf_mount(&Fs) == FR_OK) {	/* Initialize FS */
			wdt_reset();
			Buff[0] = 0;
			if (!pf_open("osccal")) pf_read(Buff, 1, &rb);	/* Adjust oscillator frequency */
			OSCCAL = org_osc + Buff[0];

			res = pf_opendir(&Dir, dir = "wav");	/* Open sound file directory */
			if (res == FR_NO_PATH) {
				res = pf_opendir(&Dir, dir = "");	/* Open root directory if no sound dir */
			}

			while (res == FR_OK) {
				res = pf_readdir(&Dir, 0);			/* Rewind dir */
				while (res == FR_OK) {				/* Play all wav files in the dir */
					wdt_reset();
					res = pf_readdir(&Dir, &Fno);		/* Get a dir entry */
					if (res || !Fno.fname[0]) break;	/* Break on error or end of dir */
					if (!(Fno.fattrib & (AM_DIR|AM_HID)) && strstr(Fno.fname, ".WAV"))
						res = play(dir, Fno.fname);		/* Play file */
				}
			}
		}
		delay500();			/* Delay 500ms in low power sleep mode */
	}
}