227 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			227 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*-----------------------------------------------------------------------*/
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/* Low level disk I/O module skeleton for Petit FatFs (C)ChaN, 2014      */
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/*-----------------------------------------------------------------------*/
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#include "pff/src/pff.h"
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#include "pff/src/diskio.h"
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void init_spi (void);		/* Initialize SPI port (asmfunc.S) */
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void deselect (void);		/* Select MMC (asmfunc.S) */
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void select (void);			/* Deselect MMC (asmfunc.S) */
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void xmit_spi (BYTE d);		/* Send a byte to the MMC (asmfunc.S) */
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BYTE rcv_spi (void);		/* Send a 0xFF to the MMC and get the received byte (asmfunc.S) */
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void dly_100us (void);		/* Delay 100 microseconds (asmfunc.S) */
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/*--------------------------------------------------------------------------
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   Module Private Functions
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---------------------------------------------------------------------------*/
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/* Definitions for MMC/SDC command */
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#define CMD0	(0x40+0)	/* GO_IDLE_STATE */
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#define CMD1	(0x40+1)	/* SEND_OP_COND (MMC) */
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#define	ACMD41	(0xC0+41)	/* SEND_OP_COND (SDC) */
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#define CMD8	(0x40+8)	/* SEND_IF_COND */
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#define CMD16	(0x40+16)	/* SET_BLOCKLEN */
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#define CMD17	(0x40+17)	/* READ_SINGLE_BLOCK */
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#define CMD24	(0x40+24)	/* WRITE_BLOCK */
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#define CMD55	(0x40+55)	/* APP_CMD */
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#define CMD58	(0x40+58)	/* READ_OCR */
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/* Card type flags (CardType) */
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#define CT_MMC				0x01	/* MMC ver 3 */
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#define CT_SD1				0x02	/* SD ver 1 */
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#define CT_SD2				0x04	/* SD ver 2 */
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#define CT_BLOCK			0x08	/* Block addressing */
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static
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BYTE CardType;
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/*-----------------------------------------------------------------------*/
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/* Send a command packet to MMC                                          */
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/*-----------------------------------------------------------------------*/
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static
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BYTE send_cmd (
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	BYTE cmd,		/* 1st byte (Start + Index) */
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	DWORD arg		/* Argument (32 bits) */
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)
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{
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	BYTE n, res;
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	if (cmd & 0x80) {	/* ACMD<n> is the command sequense of CMD55-CMD<n> */
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		cmd &= 0x7F;
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		res = send_cmd(CMD55, 0);
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		if (res > 1) return res;
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	}
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	/* Select the card */
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	select();
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	/* Send a command packet */
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	xmit_spi(cmd);						/* Start + Command index */
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	xmit_spi((BYTE)(arg >> 24));		/* Argument[31..24] */
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	xmit_spi((BYTE)(arg >> 16));		/* Argument[23..16] */
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	xmit_spi((BYTE)(arg >> 8));			/* Argument[15..8] */
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	xmit_spi((BYTE)arg);				/* Argument[7..0] */
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	n = 0x01;							/* Dummy CRC + Stop */
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	if (cmd == CMD0) n = 0x95;			/* Valid CRC for CMD0(0) */
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	if (cmd == CMD8) n = 0x87;			/* Valid CRC for CMD8(0x1AA) */
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	xmit_spi(n);
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	/* Receive a command response */
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	n = 10;								/* Wait for a valid response in timeout of 10 attempts */
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	do {
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		res = rcv_spi();
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	} while ((res & 0x80) && --n);
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	return res;			/* Return with the response value */
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}
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/*--------------------------------------------------------------------------
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   Public Functions
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---------------------------------------------------------------------------*/
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/*-----------------------------------------------------------------------*/
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/* Initialize Disk Drive                                                 */
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/*-----------------------------------------------------------------------*/
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DSTATUS disk_initialize (void)
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{
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	DSTATUS stat;
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	BYTE n, cmd, ty, ocr[4];
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	UINT tmr;
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	init_spi();							/* Initialize ports to control MMC */
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	for (n = 100; n; n--) dly_100us();	/* 10ms delay */
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	for (n = 10; n; n--) deselect();	/* 80 Dummy clocks with CS=H */
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	ty = 0;
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	if (send_cmd(CMD0, 0) == 1) {			/* Enter Idle state */
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		if (send_cmd(CMD8, 0x1AA) == 1) {	/* SDv2 */
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			for (n = 0; n < 4; n++) ocr[n] = rcv_spi();		/* Get trailing return value of R7 resp */
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			if (ocr[2] == 0x01 && ocr[3] == 0xAA) {			/* The card can work at vdd range of 2.7-3.6V */
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				for (tmr = 10000; tmr && send_cmd(ACMD41, 1UL << 30); tmr--) dly_100us();	/* Wait for leaving idle state (ACMD41 with HCS bit) */
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				if (tmr && send_cmd(CMD58, 0) == 0) {		/* Check CCS bit in the OCR */
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					for (n = 0; n < 4; n++) ocr[n] = rcv_spi();
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					ty = (ocr[0] & 0x40) ? CT_SD2 | CT_BLOCK : CT_SD2;	/* SDv2 (HC or SC) */
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				}
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			}
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		} else {							/* SDv1 or MMCv3 */
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			if (send_cmd(ACMD41, 0) <= 1) 	{
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				ty = CT_SD1; cmd = ACMD41;	/* SDv1 */
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			} else {
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				ty = CT_MMC; cmd = CMD1;	/* MMCv3 */
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			}
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			for (tmr = 10000; tmr && send_cmd(cmd, 0); tmr--) dly_100us();	/* Wait for leaving idle state */
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			if (!tmr || send_cmd(CMD16, 512) != 0)			/* Set R/W block length to 512 */
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				ty = 0;
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		}
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	}
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	CardType = ty;
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	deselect();
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	stat = ty ? 0 : STA_NOINIT;
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	return stat;
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}
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/*-----------------------------------------------------------------------*/
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/* Read Partial Sector                                                   */
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/*-----------------------------------------------------------------------*/
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DRESULT disk_readp (
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	BYTE* buff,		/* Pointer to the destination object */
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	DWORD sector,	/* Sector number (LBA) */
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	UINT offset,	/* Offset in the sector */
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	UINT count		/* Byte count (bit15:destination) */
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)
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{
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	DRESULT res;
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	BYTE rc;
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	WORD bc;
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	if (!(CardType & CT_BLOCK)) sector *= 512;		/* Convert to byte address if needed */
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	res = RES_ERROR;
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	if (send_cmd(CMD17, sector) == 0) {		/* READ_SINGLE_BLOCK */
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		bc = 40000;
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		do {							/* Wait for data packet */
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			rc = rcv_spi();
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		} while (rc == 0xFF && --bc);
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		if (rc == 0xFE) {				/* A data packet arrived */
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			bc = 514 - offset - count;
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			/* Skip leading bytes */
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			if (offset) {
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				do rcv_spi(); while (--offset);
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			}
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			/* Receive a part of the sector */
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			do {
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				*buff++ = rcv_spi();
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			} while (--count);
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			/* Skip trailing bytes and CRC */
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			do rcv_spi(); while (--bc);
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			res = RES_OK;
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		}
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	}
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	deselect();
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	return res;
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}
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/*-----------------------------------------------------------------------*/
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/* Write Partial Sector                                                  */
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/*-----------------------------------------------------------------------*/
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/*
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DRESULT disk_writep (
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	const BYTE* buff,	// Pointer to the data to be written, NULL:Initiate/Finalize write operation 
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	DWORD sc		// Sector number (LBA) or Number of bytes to send 
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)
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{
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	DRESULT res;
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	if (!buff) {
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		if (sc) {
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			// Initiate write process
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		} else {
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			// Finalize write process
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		}
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	} else {
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		// Send data to the disk
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	}
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	return res;
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}
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*/
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