mmc.h

PIC MMC and FAT Sample code

// MMC Pin Assignments
#DEFINE	MMC_CS		PIN_C0	// Active Low Chip Select.
#DEFINE	MMC_CD		PIN_C1	// Active Low card detect pin.
#DEFINE	MMC_SCLK		PIN_C3	// Connected to SCK pin of PIC.
#DEFINE	MMC_DO		PIN_C4	// Connected to SDI pin of PIC.
#DEFINE	MMC_DI		PIN_C5	// Connected to SDO pin of PIC.

// SPI Mode MMC Command Indexes (With transmission bit ie 6th bit set)
#DEFINE	MMC_CMD_GO_IDLE_STATE			0x40	//	Resets the MultiMediaCard
#DEFINE	MMC_CMD_SEND_OP_COND				0x41	//	Activates the card's initialization process.
#DEFINE	MMC_CMD_SEND_CSD					0x49	//	Asks the selected card to send its card-specific data (CSD).
#DEFINE	MMC_CMD_SEND_CID					0x4A	//	Asks the selected card to send its card identification (CID).
#DEFINE	MMC_CMD_STOP_TRANSMISSION		0x4C	// Stop transmission on multiple block read.
#DEFINE	MMC_CMD_SEND_STATUS				0x4D	//	Asks the selected card to send its status register.
#DEFINE	MMC_CMD_SET_BLOCKLEN				0x50	//	Selects a block length (in bytes) for all following block commands (read and write).
#DEFINE	MMC_CMD_READ_SINGLE_BLOCK		0x51	//	Reads a block of the size selected by the SET_BLOCKLEN command.
#DEFINE	MMC_CMD_READ_MULTIPLE_BLOCK	0x52	//	Continuously transfers data blocks from card to host until interrupted by a Stop command or the requested number of data blocks transmitted.
#DEFINE	MMC_CMD_WRITE_BLOCK				0x58	//	Writes a block of the size selected by the SET_BLOCKLEN command.
#DEFINE	MMC_CMD_WRITE_MULTIPLE_BLOCK	0x59	//	Continuously writes blocks of data until a 'Stop Tran' Token or the requested number of blocks received.
#DEFINE	MMC_CMD_PROGRAM_CSD				0x5B	//	Programming of the programmable bits of the CSD.
#DEFINE	MMC_CMD_SET_WRITE_PROT			0x5C	//	If the card has write protection features, this command sets the write protection bit of the addressed group. The properties of write protection are coded in the card specific data (WP_GRP_SIZE).
#DEFINE	MMC_CMD_CLR_WRITE_PROT			0x5D	//	If the card has write protection features, this command clears the write protection bit of the addressed group.
#DEFINE	MMC_CMD_SEND_WRITE_PROT			0x5E	//	If the card has write protection features, this command asks the card to send the status of the write protection bits.
#DEFINE	MMC_CMD_TAG_SECTOR_START		0x60	//	Sets the address of the first sector of the erase group.
#DEFINE	MMC_CMD_TAG_SECTOR_END			0x61	//	Sets the address of the last sector in a continuous range within the selected erase group, or the address of a single sector to be selected for erase.
#DEFINE	MMC_CMD_UNTAG_SECTOR				0x62	//	Removes one previously selected erase group from the erase selection.
#DEFINE	MMC_CMD_TAG_ERASE_GROUP_START	0x63	//	Sets the address of the first erase group within a continuous range to be selected for erase.
#DEFINE	MMC_CMD_TAG_ERASE_GROUP_END	0x64	//	Sets the address of the last erase group within a continuous range to be selected for erase.
#DEFINE	MMC_CMD_UNTAG_ERASE_GROUP		0x65	//	Removes one previously selected erase group from the erase selection.
#DEFINE	MMC_CMD_ERASE						0x66	//	Erases all previously selected sectors.
#DEFINE	MMC_CMD_LOCK_UNLOCK				0x6A	//	Used to set/reset the password or lock/unlock the card. The size of the Data Block is defined by the SET_BLOCK_LEN command.
#DEFINE	MMC_CMD_READ_OCR					0x7A	//	Reads the OCR register of a card.
#DEFINE	MMC_CMD_CRC_ON_OFF				0x7B	//	Turns the CRC option on or off. A '1' in the CRC option bit will turn the option on, a '0' will turn it off.

// MMC-SPI Command Format
// Command transmission always starts with the left bit of the bit string.
//typedef struct {		
//	BYTE	cmd;					//	B7 - '0', B6 - '1', B5:0 - Command Index
//	DWORD	arg;					//	B39:8 - Argument
//	BYTE	crc;					//	B7:1 - CRC7, B0 - '1'
//} MMCCOMMAND;
//MMCCOMMAND command;			// Global variable.

// MMC-SPI R1 Response Format
//typedef struct {		
//	BOOL	reserved;						// Reserved at value '0'.
//	BOOL	parameterError;				//	The command's argument (for example, address, block length) was out of the allowed range for this card.
//	BOOL	addressError;					//	A misaligned address, which did not match the block length, was used in the command.
//	BOOL	erase_Seq_Error;				//	An error occurred in the sequence of erase commands.
//	BOOL	comCRCError;					//	The CRC check of the last command field.
//	BOOL	illegalCommand;				//	An illegal command code was detected.
//	BOOL	eraseReset;						//	An erase sequence was cleared before executing because an out of erase sequence command was received.
//	BOOL	idleState;						//	The card is in idle state and running the initializing process.
//} MMCRESPONSE;


// MMC-SPI Status Response Format
// A SEND_STATUS command will give a response of R1 followed by the following Status Response byte.
//typedef struct {		
//	BOOL	outOfRange_CSD_Overwrite;	// This status bit has two functions. It is set if the command argument was out of its valid range, or if the host is trying to change the ROM section or reverse the copy bit (set as original) or permanent WP bit (un-protect) of the CSD register.
//	BOOL	eraseParam;						//	An invalid selection, sectors or groups, for erase.
//	BOOL	writeProtectViolation;		//	The command tried to write a write-protected block.
//	BOOL	cardECCFailed;					//	Card internal ECC was applied but failed to correct the data.
//	BOOL	cCError;							//	Internal card controller error.
//	BOOL	error;							//	A general or an unknown error occurred during the operation.
//	BOOL	writeProtect_PasswordErr;	// An erase sequence was cleared before executing because an out of erase sequence command was received.
//	BOOL	cardIsLocked;					//	This bit is set when the card is locked by the user. It is reset when it is unlocked.
//} MMCSTATUS;

//	MMC-SPI Data Response Format
//	Every block will be ackowledged by a data response token.
//typedef struct {		
//	BYTE	unused	:	4;					//	B7:4 - Don't Care, B4 - '0'.
//	BYTE	status	:	3;					// B3:1 - Status (2=Data accepted,5=Data rejected due to a CRC error,6=Data rejected due to a Write error.)
//	BYTE	reserved	:	1;					// B0 - '1'
//} MMCDATARESPONSE;
#DEFINE	MMCDATAOK		4
#DEFINE	MMCCRCERROR		10
#DEFINE	MMCWRITEERROR	12

// MMC-SPI Data Tokens
#DEFINE	MMCSTARTSINGLEREAD		0xFE
#DEFINE	MMCSTARTMULTIPLEREAD		0xFE
#DEFINE	MMCSTARTSINGLEWRITE		0xFE
#DEFINE	MMCSTARTMULTIPLEWRITE	0xFC
#DEFINE	MMCSTOPTRANSACTION		0xFD

// MMC-SPI Data Error Token
//typedef struct {		
//	BYTE	reserved	:	3;					//	B7:5 - '0'.
//	BOOL	error;							//	A general or an unknown error occurred during the operation.
//	BOOL	cCError;							//	Internal card controller error.
//	BOOL	cardECCFailed;					//	Card internal ECC was applied but failed to correct the data.
//	BOOL	outOfRange;						// Set if the read/write was out of its valid range.
//	BOOL	cardIsLocked;					//	This bit is set when the card is locked by the user. It is reset when it is unlocked.
//} MMCDATAERROR;

// Function Prototypes
BOOL mmcDetect();
#SEPARATE BOOL mmcInit();
#SEPARATE BYTE mmcSendCmd(BYTE cmd,DWORD arg,BYTE crc);
void mmcSetBlockLength(DWORD length);
BYTE mmcReadSingleByte(DWORD address);
void mmcDumpResponse(BYTE response);
BYTE mmcGetStatus();
#SEPARATE void mmcDumpCSD();
#SEPARATE void mmcDumpCID();

// Global Variables
BYTE mmcWriteBuffer[512];							// Buffer to be used for MMC write operations