mmc.h

Interfacing to an MMC/SD card via SPI (for microcontroller)

// Author        : Pascal Stang - Copyright (C) 2004
// Modified    : Tony Ward, Cyan Technology, March 2006
//
///        This library offers some simple functions which can be used
///        to read and write data on a MultiMedia or SecureDigital (SD) Flash
///        Card.  Although MM and SD Cards are designed to operate with their own
///        special bus wiring and protocols, both types of cards also provide a
///        simple SPI-like interface mode which is exceptionally useful when 
///        attempting to use the cards in embedded systems.
///
///        (*) you must define this chip select I/O pin in mmcConf.h
//
// This code is distributed under the GNU Public License
//        which can be found at http://www.gnu.org/licenses/gpl.txt
//
//   TWard March 2006 - Ported software to eCOG1k micro under CyanIDE
//                      and added working support for the SD card interface
//*****************************************************************************

#ifndef MMC_H
#define MMC_H

// Leave this here to allow debugging functions and messages
//#define MMC_DEBUG


// constants/macros/typdefs
// MMC commands (taken from sandisk MMC reference)
#define MMC_GO_IDLE_STATE                0        ///< initialize card to SPI-type access
#define MMC_SEND_OP_COND                 1        ///< set card operational mode
#define MMC_SEND_CSD                     9        ///< get card's CSD
#define MMC_SEND_CID                    10        ///< get card's CID
#define MMC_SEND_STATUS                 13
#define MMC_SET_BLOCKLEN                16        ///< Set number of bytes to transfer per block
#define MMC_READ_SINGLE_BLOCK           17        ///< read a block
#define MMC_WRITE_BLOCK                 24        ///< write a block
#define MMC_PROGRAM_CSD                 27
#define MMC_SET_WRITE_PROT              28
#define MMC_CLR_WRITE_PROT              29
#define MMC_SEND_WRITE_PROT             30
#define MMC_TAG_SECTOR_START            32
#define MMC_TAG_SECTOR_END              33
#define MMC_UNTAG_SECTOR                34
#define MMC_TAG_ERASE_GROUP_START       35        ///< Sets beginning of erase group (mass erase)
#define MMC_TAG_ERARE_GROUP_END         36        ///< Sets end of erase group (mass erase)
#define MMC_UNTAG_ERASE_GROUP           37        ///< Untag (unset) erase group (mass erase)
#define MMC_ERASE                       38        ///< Perform block/mass erase
#define MMC_CRC_ON_OFF                  59        ///< Turns CRC check on/off

// R1 Response bit-defines
#define MMC_R1_BUSY                     0x80    ///< R1 response: bit indicates card is busy
#define MMC_R1_PARAMETER                0x40
#define MMC_R1_ADDRESS                  0x20
#define MMC_R1_ERASE_SEQ                0x10
#define MMC_R1_COM_CRC                  0x08
#define MMC_R1_ILLEGAL_COM              0x04
#define MMC_R1_ERASE_RESET              0x02
#define MMC_R1_IDLE_STATE               0x01

// Data Start tokens
#define MMC_STARTBLOCK_READ             0xFE    ///< when received from card, indicates that a block of data will follow
#define MMC_STARTBLOCK_WRITE            0xFE    ///< when sent to card, indicates that a block of data will follow
#define MMC_STARTBLOCK_MWRITE           0xFC

// Data Stop tokens
#define MMC_STOPTRAN_WRITE              0xFD

// Data Error Token values
#define MMC_DE_MASK                     0x1F
#define MMC_DE_ERROR                    0x01
#define MMC_DE_CC_ERROR                 0x02
#define MMC_DE_ECC_FAIL                 0x04
#define MMC_DE_OUT_OF_RANGE             0x04
#define MMC_DE_CARD_LOCKED              0x04

// Data Response Token values
#define MMC_DR_MASK                     0x1F
#define MMC_DR_ACCEPT                   0x05
#define MMC_DR_REJECT_CRC               0x0B
#define MMC_DR_REJECT_WRITE_ERROR       0x0D

// Function Prototypes

//! Initialize AVR<->MMC hardware interface.
/// Prepares hardware for MMC access.
void mmcInit(void);

//! Initialize the card and prepare it for use.
/// Returns zero if successful.
unsigned int mmcReset(void);

//! Send card an MMC command.
/// Returns R1 result code.
unsigned int mmcSendCommand(unsigned int cmd, unsigned long arg);

//! Read 512-byte sector from card to buffer
/// Returns zero if successful.
unsigned int mmcRead(unsigned long sector, unsigned char *buffer);

//! Write 512-byte sector from buffer to card
/// Returns zero if successful.
unsigned int mmcWrite(unsigned long sector, unsigned char *buffer);

//! Internal command function.
/// Issues a generic MMC command as specified by cmd and arg.
unsigned int mmcCommand(unsigned int cmd, unsigned long arg);

void __irq_entry GPIO_Handler (void) ;

#endif