How can I use SRAM on atmega128 ?

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#1
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Total votes: 0

Guys,

How can I use SRAM on atmega128 ?
I want to read from SDcard 512bytes and then send those 512bytes into VS1003...
I can read from sdcard, and sending bytes to VS1003 on a different function, not yet combined...

Any ideas ?
thanks for the advice

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Total votes: 0

You really didn't think too carefully about this question did you?

Let me hazard to guess you're not really interested in the sram but rather want to know how to pass the buffer across in C? If you're using fatfs, then you pass it a pointer to where you want the data. Past this point you've given us no idea of what your vs1003 function looks like.
So, show us your code.

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here's the code for reading from SD
readFile( READ, "test.mp3");

and here's for playing it on VS1003

while (p <= &HelloMP3[sizeof(HelloMP3)-1])
{
VS1003B_WriteByte(pgm_read_byte(p++));
}

for now I took HelloMP3 from an array of bytes, and I want to replace those bytes with the bytes from SDcard...

any suggestions ?

thanks

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Total votes: 0

Why do you need to buffer so much data? Surely the 512 byte sector buffer that FatFs uses is sufficient?

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How can I transfer those bytes from

f=readFile( READ, "a.mp3");

into

p = f ?

while (p <= f[sizeof(f)-1])
		{
			VS1003B_WriteByte((p++));
		}

for a test before, it's working

const unsigned char HelloMP3[] __attribute__ ((progmem))= {
	0xFF,0xF2,0x40,0xC0,0x19,0xB7,0x00,0x14,0x02,0xE6,0x5C, /* ..@.......\ */
	0x01,0x92,0x68,0x01,0xF1,0x5E,0x03,0x08,0xF0,0x24,0x80, /* ..h..^...$. */
	0x05,0x9E,0x20,0xC6,0xFC,0x12,0x32,0x5C,0xBF,0xF9,0xB9, /* .. ...2\... */
	0x20,0x4A,0x7F,0x85,0xEC,0x4C,0xCD,0xC7,0x27,0xFE,0x5C, /*  J...L..'.\ */
	0x34,0x25,0xCB,0xE6,0xFF,0xFF,0x8E,0x42,0xE1,0xA0,0x5E, /* 4%.....B..^ */
	0xCA,0x6E,0x30,0x9F,0xFF,0xF8,0xC2,0x12,0x84,0xB9,0x7C, /* .n0.......| */
	0xDC,0x61,0x09,0x4A,0x7F,0xFF,0xFF,0xF9,0x7D,0x32,0x51, /* .a.J....}2Q */
	0x09,0x7C,0xE1,0xA5,0x6E,0xB4,0xFF,0xFF,0xFF,0xFF,0xD3, /* .|..n...... */
	0x34,0x41,0x91,0xF0,0x11,0x8F,0x00,0x0F,0x81,0x9C,0x10, /* 4A......... */
	0xEE,0x59,0xCE,0x56,0x67,0xFF,0xF2,0x42,0xC0,0xEC,0x53, /* .Y.Vg..B..S */
	0x09,0x15,0xF9,0xAA,0xA8,0x0D,0xD9,0x40,0x00,0xCA,0x34, /* .......@..4 */
	0x53,0xD9,0x18,0xAB,0x7D,0xF7,0x89,0x3F,0x11,0x38,0x94, /* S...}..?.8. */
	0x82,0x59,0x93,0x20,0x6A,0x0C,0xEE,0x8E,0x58,0xFA,0x38, /* .Y. j...X.8 */
	0x82,0xCA,0xF0,0x58,0xBB,0xDA,0x0C,0x50,0x56,0x1F,0xBB, /* ...X...PV.. */
	0x18,0x5D,0x8B,0x9F,0xDA,0x71,0x4F,0xFF,0xBD,0xFE,0xEF, /* .]...qO.... */
	0x69,0x36,0x86,0x3C,0x50,0xBB,0x0A,0x07,0x89,0x54,0xF0, /* i6. .(4.... */
	0xC0,0x01,0x75,0xF8,0x05,0x6B,0x5F,0x41,0x17,0x0B,0xE7, /* ..u..k_A... */
	0xFF,0xF2,0x40,0xC0,0x61,0xE5,0x0B,0x16,0x09,0xC6,0xC5, /* ..@.a...... */
	0x74,0x7B,0xCC,0x94,0x7A,0xF7,0x80,0x76,0xB2,0xD2,0xF8, /* t{..z..v... */
		0x39,0x06,0x38,0xFD,0x71,0xC5,0xDE,0x3A,0x38,0xBF,0xD5, /* 9.8.q..:8.. */
		0xF7,0x12,0x37,0xCB,0xF5,0x63,0x0C,0x9B,0xCE,0x77,0x25, /* ..7..c...w% */
		0xED,0xFB,0x3D,0x6B,0x35,0xF9,0x6D,0xD7,0xF9,0x2C,0xD1, /* ..=k5.m..,. */
		0x97,0x15,0x87,0x93,0xA4,0x49,0x4A,0x18,0x16,0x07,0xA1, /* .....IJ.... */
		0x60,0xF7,0x52,0x94,0xDB,0x02,0x16,0x70,0xB2,0xD8,0x80, /* `.R....p... */
		0x30,0xC2,0x94,0x40,0x81,0x74,0x5A,0x19,0x7A,0x80,0x60, /* 0..@.tZ.z.` */
		0x41,0x21,0x46,0x95,0xD5,0xC4,0x40,0xD2,0x01,0xC0,0x01, /* A!F...@.... */
		0xDA,0xD9,0xA0,0xB1,0x01,0xFF,0xF2,0x42,0xC0,0x82,0x10, /* .......B... */
		0x0B,0x12,0xF9,0x9E,0xC9,0x7E,0x7A,0xC6,0x95,0x55,0x09, /* .....~z..U. */
		0x8B,0x19,0x5E,0x8B,0x26,0xCA,0xEB,0x68,0x8A,0x05,0x8F, /* ..^.&..h... */
		0x36,0xA5,0xA5,0x03,0xB8,0x9C,0xED,0x24,0x51,0x59,0x90, /* 6......$QY. */
		0xF6,0xC5,0x7D,0xB5,0xAD,0xAF,0xF6,0x3B,0x18,0xEF,0x3F, /* ..}....;..? */
		0xFF,0xFF,0x4E,0xDE,0x16,0x66,0x0B,0xAA,0x33,0x23,0xDD, /* ..N..f..3#. */
		0x9C,0x4E,0x6E,0x55,0x22,0x9D,0xA2,0x40,0xA6,0x36,0x31, /* .NnU"..@.61 */
		0x69,0xA5,0xE1,0xD9,0x7F,0xF7,0xC6,0xCC,0x48,0x00,0x0E, /* i.......H.. */
		0x90,0x16,0x00,0x0F,0xDE,0x6E,0x80,0x11,0x0C,0x9A,0x4F, /* .....n....O */
		0x56,0xDB,0x88,0xD3,0xB2,0x1C,0x00,0xE0,0x2E,0x3E,0xAC, /* V........>. */
		0xFF,0xF2,0x40,0xC0,0x1C,0xE5,0x19,0x13,0x31,0x4E,0xCD, /* ..@.....1N. */
		0x9E,0xC3,0x06,0x71,0x03,0x85,0xE5,0xB5,0x6D,0x88,0x50, /* ...q....m.P */
		0x8E,0x0E,0x17,0x3B,0x19,0xFB,0x4E,0x3B,0x99,0xEF,0x4C, /* ...;..N;..L */
		0x9E,0xF7,0x7B,0x31,0x7C,0x3C,0x5F,0xFF,0xF4,0xF8,0xE3, /* ..{1|<_.... */
			0x92,0x42,0x07,0x8E,0x83,0x8E,0x0F,0x05,0x08,0x91,0xA3, /* .B......... */
			0x16,0xE2,0xDF,0xB7,0x62,0x60,0x48,0x31,0x3C,0xFF,0xD4, /* ....b`H1<.. */
			0x9E,0x0C,0x68,0x00,0x77,0x54,0xE3,0x1E,0x05,0xC5,0xF8, /* ..h.wT..... */
			0xEA,0x8D,0x82,0x9D,0x08,0xA9,0x06,0x8D,0x1E,0x5D,0x7C, /* .........]| */
			0x7F,0x08,0xC0,0x50,0x45,0x42,0xD0,0x36,0xF8,0xB2,0x4D, /* ...PEB.6..M */
			0x53,0x0C,0x80,0x3B,0x4D,0xFF,0xF2,0x42,0xC0,0x2F,0x3C, /* S..;M..B./< */
			0x25,0x19,0x29,0xFE,0xBC,0x2E,0xC4,0xD0,0x99,0x4C,0x48, /* %.)......LH */
			0xB0,0x9C,0x49,0xD2,0x1A,0x2D,0x02,0xC2,0x79,0x69,0x16, /* ..I..-..yi. */
			0x92,0xA8,0xC5,0xAB,0x45,0x5A,0x68,0xE8,0x75,0x57,0xCD, /* ....EZh.uW. */
			0xF1,0xB9,0xAA,0x13,0x88,0xE4,0x87,0x42,0x15,0xB3,0x58, /* .......B..X */
			0xF5,0xA3,0x46,0xB1,0xCF,0xD3,0x59,0x7E,0xBA,0xB5,0xA7, /* ..F...Y~... */
			0x6B,0x0B,0x17,0x57,0x6B,0x5C,0x4A,0xCD,0x53,0x76,0x2A, /* k..Wk\J.Sv* */
			0x1D,0x28,0xC5,0x1C,0x76,0x5C,0xDD,0x0A,0x00,0x4B,0xC0, /* .(..v\...K. */
			0x1B,0xCA,0xA8,0xE9,0x81,0x5B,0xA6,0xDC,0xA4,0x59,0x13, /* .....[...Y. */
			0xFC,0xBA,0x8F,0x98,0x79,0x44,0x25,0xC9,0x35,0x38,0xCA, /* ....yD%.58. */
			0xFF,0xF2,0x40,0xC0,0xB9,0x7D,0x1A,0x13,0x79,0x6A,0xC8, /* ..@..}..yj. */
			0x3E,0xC4,0x46,0x94,0x8D,0x3C,0x67,0x85,0xB1,0xA8,0x89, /* >.F...n.f.. */
				0xE3,0xC2,0xE0,0x29,0x43,0x87,0x5F,0x4F,0x27,0x9C,0x2C, /* ...)C._O'., */
				0xD0,0x91,0xF3,0x87,0x9B,0x54,0xED,0xD1,0xB4,0xF3,0x39, /* .....T....9 */
				0x87,0x22,0x06,0x86,0x0D,0x71,0xE4,0x6F,0x2A,0x08,0x04, /* ."...q.o*.. */
				0xC0,0x03,0x2A,0xB1,0xE2,0x05,0x4D,0x64,0xA1,0x9C,0xA6, /* ..*...Md... */
				0x0D,0x41,0xA6,0xF2,0x7A,0xC1,0x30,0xC3,0x38,0x26,0x09, /* .A..z.0.8&. */
				0x50,0x08,0xC4,0xF6,0x30,0x0C,0xA6,0xA9,0x17,0x00,0x13, /* P...0...... */
				0x0C,0xDC,0xC4,0x2F,0x28,0xEB,0x3F,0xCD,0x7A,0x3D,0x2F, /* .../(.?.z=/ */
				0xFF,0xF2,0x40,0xC0,0x18,0x6F,0x2E,0x13,0xA1,0xF2,0xBC, /* ..@..o..... */
				0x36,0xCB,0x4E,0x99,0x6E,0xFC,0xEE,0xC5,0xF0,0xA0,0xB7, /* 6.N.n...... */
				0x92,0xD4,0xEE,0x79,0x7C,0x50,0x5D,0xE5,0x04,0x94,0xA9, /* ...y|P].... */
				0x76,0xCF,0x6C,0x70,0xDD,0x0D,0xD4,0xEE,0xED,0x98,0xE8, /* v.lp....... */
				0xC8,0x35,0x36,0x7A,0x0C,0x05,0x80,0x03,0xBC,0xBE,0x91, /* .56z....... */
				0x00,0x7C,0xAE,0x65,0xB8,0x91,0xA3,0x33,0xBA,0x68,0x60, /* .|.e...3.h` */
				0xD4,0x1A,0x66,0xF8,0x43,0xA0,0x20,0x89,0xE7,0x80,0xD8, /* ..f.C. .... */
				0x1E,0x4F,0xA0,0x04,0x60,0x06,0x0A,0xA4,0x91,0x24,0xFA, /* .O..`....$. */
				0x9F,0x57,0x53,0xF4,0x7A,0xDB,0x5F,0x56,0xE3,0x6E,0x0B, /* .WS.z._V.n. */
				0x8B,0x3A,0x1C,0xF9,0x5E,0xFF,0xF2,0x42,0xC0,0xB1,0x00, /* .:..^..B... */
				0x38,0x14,0x09,0xEE,0xB4,0x36,0xD3,0x4E,0x99,0xA4,0x78, /* 8....6.N..x */
				0x94,0x73,0xC4,0x66,0x30,0xF5,0xEA,0xDB,0xBA,0x67,0x67, /* .s.f0....gg */
				0x95,0x6B,0xAB,0x68,0x5D,0x08,0xA1,0x39,0x56,0xAB,0x1E, /* .k.h]..9V.. */
				0xD5,0x03,0xE8,0x01,0x70,0x00,0xB3,0x93,0x33,0x19,0x8C, /* ....p...3.. */
				0x61,0x8F,0xBB,0x5D,0x24,0x12,0x63,0xD3,0x4B,0x5D,0x91, /* a..]$.c.K]. */
				0x08,0x43,0x22,0x56,0x1A,0xC5,0x10,0x21,0x84,0xA8,0xEA, /* .C"V...!... */
				0x80,0xBF,0x16,0x8E,0x3D,0x46,0x18,0x9C,0x6E,0x9A,0x91, /* ....=F..n.. */
				0xE6,0xC9,0x6F,0xD2,0x7D,0x27,0xD7,0xE9,0x6B,0xFF,0x0A, /* ..o.}'..k.. */
				0x03,0x43,0x89,0xD5,0xBF,0x52,0x97,0x0A,0x25,0x95,0x0D, /* .C...R..%.. */
				0xFF,0xF2,0x40,0xC0,0xF5,0xC3,0x41,0x13,0x81,0xEE,0xA8, /* ..@...A.... */
				0x5E,0xD3,0x44,0x98,0xFC,0xCF,0x97,0xF9,0x58,0xB5,0x33, /* ^.D.....X.3 */
				0xB1,0x85,0x47,0x86,0xD7,0x98,0x01,0x3B,0xA3,0x4F,0x7E, /* ..G....;.O~ */
				0x04,0xA6,0xC3,0x39,0x21,0x70,0x27,0x62,0xB5,0x18,0x10, /* ...9!p'b... */
				0x09,0x99,0x00,0x8B,0x7E,0xF2,0xBF,0x52,0x18,0x26,0x30, /* ....~..R.&0 */
				0x1C,0xB0,0x01,0x49,0x30,0xE0,0xC3,0x11,0x46,0x05,0xCC, /* ...I0...F.. */
				0x49,0x14,0x28,0xB2,0xED,0x4B,0x57,0x5A,0x2F,0xB7,0x46, /* I.(..KWZ/.F */
				0x63,0x34,0xD2,0xDA,0x9F,0x56,0x32,0xB7,0xA2,0x25,0xFF, /* c4...V2..%. */
				0x94,0x28,0x33,0x7F,0x3B,0xC4,0x50,0xEC,0xB1,0xE2,0x26, /* .(3.;.P...& */
				0xA1,0xB7,0x07,0x7F,0xFB,0xFF,0xF2,0x42,0xC0,0x67,0x6A, /* .......B.gj */
				0x4C,0x13,0xF9,0x6A,0x90,0x7E,0xDB,0x44,0x94,0x3F,0xFF, /* L..j.~.D.?. */
				0x14,0xD6,0x2A,0xFF,0xFF,0xC1,0x34,0x8C,0x48,0x22,0x00, /* ..*...4.H". */
				0x06,0x8F,0x21,0xFD,0x64,0x60,0x04,0x92,0x42,0xEA,0x74, /* ..!.d`..B.t */
				0x32,0x37,0xAA,0x5A,0x9F,0x67,0x01,0x8B,0x3F,0x37,0x31, /* 27.Z.g..?71 */
				0xDD,0x06,0x3C,0x01,0x34,0x30,0xE0,0x5C,0x78,0x78,0xCB, /* ..<.40.\xx. */
				0xD6,0xF1,0x31,0x8A,0x69,0x61,0x93,0x92,0x42,0xCE,0x4B, /* ..1.ia..B.K */
				0xC5,0x02,0x4E,0x73,0xC6,0x24,0x30,0xCD,0x08,0x66,0xC6, /* ..Ns.$0..f. */
				0x35,0xAB,0xA2,0x3D,0x2F,0xB3,0xBD,0x34,0x87,0x13,0xEE, /* 5..=/..4... */
				0x71,0x45,0x68,0xFA,0xEA,0x05,0x84,0x41,0x36,0x4C,0x9A, /* qEh....A6L. */
				0xFF,0xF2,0x40,0xC0,0xC9,0x92,0x56,0x13,0xD0,0x6E,0x70, /* ..@...V..np */
				0x54,0xD3,0xCC,0x28,0x06,0xD7,0x0E,0xA4,0x1D,0x9C,0x9D, /* T..(....... */
				0xD9,0xA9,0x88,0x7B,0xB5,0xA3,0x56,0xB7,0x4B,0x4B,0x5A, /* ...{..V.KKZ */
					0x9B,0x2C,0xA9,0xAD,0x6F,0x99,0x6C,0xC0,0x4C,0x14,0x14, /* .,..o.l.L.. */
					0xEF,0xB4,0x20,0x91,0x5F,0xBC,0x81,0x41,0x41,0x5D,0xD4, /* .. ._..AA]. */
					0x20,0xBD,0x05,0x1A,0x6F,0xE2,0x68,0x56,0x41,0x41,0x57, /*  ...o.hVAAW */
					0xF9,0xBF,0x89,0x82,0x8E,0xC7,0x8F,0x0A,0x0A,0x09,0x37, /* ..........7 */
					0xF1,0x05,0x0A,0x0A,0x0A,0x0A,0x09,0x05,0x37,0xFF,0x10, /* ........7.. */
					0x50,0x50,0x53,0x65,0xFF,0xFF,0xFD,0x75,0xDF,0xFF,0xFF, /* PPSe...u... */
					0x68,0x4F,0xFF,0x84,0x70,0xFF,0xF2,0x42,0xC0,0x27,0x50, /* hO..p..B.'P */
					0x5F,0x17,0xE8,0x82,0x3C,0x11,0x58,0x18,0x01,0x55,0x48, /* _...<.X..UH */
					0xBC,0x52,0xFC,0x4A,0x4C,0x3C,0xD5,0xF6,0x11,0x2D,0xBF, /* .R.JL<...-. */
					0xEA,0x03,0x5C,0x57,0x29,0xBF,0xC3,0x75,0x1C,0xE6,0xDD, /* ..\W)..u... */
					0xBF,0xED,0xEF,0xD0,0x98,0x77,0x71,0x95,0x73,0xFF,0xED, /* .....wq.s.. */
					0x54,0xBE,0xD5,0xEE,0xAE,0xC2,0xD5,0x0B,0xFF,0xF1,0x97, /* T.......... */
					0x8A,0xE4,0x42,0x09,0x99,0xB1,0xEA,0x94,0xDC,0x78,0xB5, /* ..B......x. */
					0x34,0x0F,0xF1,0x8F,0xFC,0x15,0xF6,0xFA,0xB1,0x47,0xA9, /* 4........G. */
					0x6C,0x67,0x43,0x8B,0xF2,0x76,0x22,0xED,0xDA,0x85,0xBA, /* lgC..v".... */
					0x2F,0xC7,0xF9,0xCF,0xFC,0xDB,0x46,0x2E,0x50,0x0A,0x84, /* /.....F.P.. */
					0xFF,0xF2,0x40,0xC0,0xC6,0x4A,0x59,0x28,0x2B,0x19,0xE0, /* ..@..JY(+.. */
					0x01,0x89,0x78,0x00,0x52,0x85,0x3C,0x8E,0x54,0x9A,0x48, /* ..x.R.<.T.H */
					0x5A,0x72,0x32,0x94,0xBF,0x43,0x4F,0x24,0x53,0x4B,0xEC, /* Zr2..CO$SK. */
					0x4B,0x99,0x0E,0x66,0x1F,0xFF,0xCE,0x7F,0xFF,0x3F,0x10, /* K..f.....?. */
					0xAE,0x82,0x62,0x71,0x34,0x18,0x59,0x9B,0x51,0xC7,0x59, /* ..bq4.Y.Q.Y */
					0xCE,0xEE,0xA5,0xFE,0x02,0xBB,0x30,0x91,0x49,0xD5,0x4B, /* ......0.I.K */
					0xF3,0xDC,0x9A,0xA9,0x57,0x8E,0x72,0x10,0xC0,0x5D,0x60, /* ....W.r..]` */
					0x67,0xFC,0x7D,0xD6,0xBA,0xDD,0xB3,0x8B,0x5A,0x0A,0x4C, /* g.}.....Z.L */
					0x41,0x4D,0x45,0x33,0x2E,0x39,0x33,0xAA,0xAA,0xAA,0xAA, /* AME3.93.... */
					0xAA,0xAA,0xAA,0xAA,0xAA,0x54,0x41,0x47,0x48,0x65,0x6C, /* .....TAGHel */
					0x6C,0x6F,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20, /* lo          */
					0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20, /*             */
					0x20,0x20,0x20,0x20,0x20,0x50,0x61,0x6E,0x75,0x2D,0x4B, /*      Panu-K */
					0x72,0x69,0x73,0x74,0x69,0x61,0x6E,0x20,0x50,0x6F,0x69, /* ristian Poi */
					0x6B,0x73,0x61,0x6C,0x6F,0x20,0x20,0x20,0x20,0x20,0x20, /* ksalo       */
					0x20,0x20,0x56,0x53,0x44,0x53,0x50,0x20,0x54,0x65,0x73, /*   VSDSP Tes */
					0x74,0x69,0x6E,0x67,0x20,0x20,0x20,0x20,0x20,0x20,0x20, /* ting        */
					0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20, /*             */
					0x20,0x20,0x20,0x4D,0x50,0x33,0x20,0x48,0x65,0x6C,0x6C, /*    MP3 Hell */
					0x6F,0x2C,0x20,0x57,0x6F,0x72,0x6C,0x64,0x21,0x20,0x20, /* o, World!   */
					0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20, /*             */
					0x00, /* . */
				};

void VsSineTest(){
        unsigned char *p;
		unsigned int i;
		p = HelloMP3;
	    /* Reset MP3 chip */
	   /* Pull xRESET low -> hardware reset */
	    VS1003B_XRESET_L(); 
		_delay_ms(100);            /* 100 ms delay */

	    /* Send dummy SPI byte to initialize SPI bus of Atmel microcontroller */
	    VS1003B_WriteByte(0xFF);
		
	    /* Un-reset MP3 chip */
	    VS1003B_XCS_H();
		/* Pull xCS high    */
	    /* Pull xDCS high   */
	    VS1003B_XDCS_H();
		 /* Pull xRESET high */
	    VS1003B_XRESET_H();
		_delay_ms(100);            /* 100 ms delay     */

	    /* VS10xx Application Notes, chapter 4.8 ---------------------------------*/
	    /* As an example, let's write value 0x0820 to register 00 byte by byte    */
	    VS1003B_XCS_L();
		 /* Pull XCS low, now SPI writes go to SCI port     */
	    VS1003B_WriteCMD(00,0x0820);
		VS1003B_WriteCMD(SCI_VOL,0x0000); //max volume
	
		 /* Send SPI Byte, then wait for byte to be sent.   */
	     /* 0x02 was WRITE command, 0x00 is register number */
	     /* This byte goes to MSB                           */
	     /* ..and this is LSB. (0x20=Allow Test Mode)       */
	    VS1003B_Delay();
		 /* Wait until Atmel MCU signals SPI write complete */
	    VS1003B_XCS_H();
		usart_pstr("WAITING FOR DREQ ! \n");
		/* Pull XCS high, now SPI writes don't go to SCI port. */
        loop_until_bit_is_set(VS1003B_PIN,VS1003B_DREQ);
        
	    if (bit_is_set(VS1003B_PIN,VS1003B_DREQ))
		  {
	       usart_pstr("\n DREQ = 1 \n \n");
		  }else
		  {
		   usart_pstr("\n DREQ = 0 \n \n"); 	  
		  }
	    /* pull XDCS low, now SPI writes go to SDI port    */

		VS1003B_XDCS_L();
		/* Send a Sine Test Header to Data port*/
		while (p <= &HelloMP3[sizeof(HelloMP3)-1])
		{
			VS1003B_WriteByte(pgm_read_byte(p++));
		}
		      /* - This is a special VLSI Solution test header - */
	          /* - that starts a sine sound. It's good for     - */
	          /* - testing your code and the chip. */
	    
		VS1003B_Delay();
	    
	    VS1003B_XDCS_H();
	    _delay_ms(500);           /* 500 ms delay */

	    /* Stop the sine test sound */
		 VS1003B_XDCS_L();
		
	    //SPIWait();
		VS1003B_Delay();

	    //Mp3DeselectData();
        VS1003B_XDCS_H(); 
	    _delay_ms(500);            /* 500 ms delay */
		
		usart_pstr("Sine wave test 's stoped, change to SPI High! \n");
		
		VS1003B_XDCS_L(); // Pull XDCS low
		
		 
		 if (bit_is_set(VS1003B_PIN,VS1003B_DREQ))
		 {
			 usart_pstr("\n DREQ = 1 \n \n");
		 }else
		 {
			 usart_pstr("\n DREQ = 0 \n \n");
		 }
        
		for (i=0; i<2048; i++)
		{
			//while (bit_is_clear(VS1003B_PIN,VS1003B_DREQ)); // wait here until DREQ is high again
			
			VS1003B_WriteByte(0);
		}
		VS1003B_Delay(0xffff); // Wait until SPI transfer is completed
		//VS1003B_XDCS_H(); // Pull XDCS high
		_delay_ms(500);
		usart_pstr("VS1003 AND ATMEGA128 SAYING HELLO! \n \n" );
		
		
    }

I want to replace


while (p <= &HelloMP3[sizeof(HelloMP3)-1])
		{
			VS1003B_WriteByte(pgm_read_byte(p++));
		}

p <= &HelloMP3[sizeof(HelloMP3)-1]
with the file from sdcard (readfile)

any clues ? thank you

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Total votes: 0

Have you ever written a C program on a PC that uses the filing functions in stdio.h? (ie FILE, fopen, fread, fgetc, fclose, etc.)

If not now might be a good time to start. Both these and FatFs work on the principle that a file is just a stream of bytes. fgetc gets you the next byte from the stream and fread gets you the next N bytes. You don't have to worry about buffering or how the file is actually read you just read 1 or N bytes and you get them. If you want some local buffering you can declare a local [100/512/4096/whatever] byte buffer and fread 100/512/4096/whatever bytes to it each time.

So I suggest you learn all about this using stdio.h on a PC then what you learn there naturally ports to the almost identical f_open/f_read/f_close functions in FatFs.

The only reason you might need local buffering is if the VS1003 requires continuous data and you need to implement ping-pong double buffers (though I'd have thought 512 byte sector sized buffers would be enough)

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Total votes: 0

I have read it :
readFile( READ, "test.txt");
The function (readFile):

while(1)
{
  firstSector = getFirstSector (cluster);

  for(j=0; j= fileSize ) return 0;
    }
  }

so I change usart_transmit to write_byte to VS1003?

thanks

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Total votes: 0

Why not just use the normal fread function?
Rather than post a solution as a question, why dont you try it first?

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Why on eart hwould you be worrying about getFirstSector(cluster) and reading single blocks??

The whole point of FatFs() (like stdio filing) is that it abstracts you from the storage implementation. You can fopen() files on a PC and not know whether they are on HDD, USB-MSD, SD/MMC, NAS, RAM disk or whatever and you don't need to know where or how the data is stored. On HDD for example it could be FAT, NTFS, EXT2/3/4, whatever but you don't need to know about blocks and clusters and such.

So it is with FatFs(). For the PC version Chan even shows examples that work identically for HDD, SD/MMC, USB, ConpactFlash etc. True on the AVR there's a pretty strong chance you are going to use it with 512 byte sector SD/MMC cards with a a FAT12/16/32 structure driven over SPI-MMC but there's no reason your application level code needs to know anything about that or FAT or clusters.

So just do what Chan intended. f_open() the file then f_read() it. Let FatFs do the hidden sector buffering for you.