M24LR64E Class Reference

C++ API for the M24LR64E NFC Tag. More...

Detailed Description

• ID: m24lr64e
• Name: Dynamic NFC/RFID Tag Module
• Other Names: Grove NFC Tag
• Category: other
• Manufacturer: seeed
• Link: http://www.seeedstudio.com/wiki/Grove_-_NFC_Tag
• Connection: i2c

The M24LR64E NFC tag is an 8KB electrically erasable programmable read-only memory (EEPROM) that can be written to or read from using I2C and NFC-equipped devices.

The user mode (default) allows read and write access to all 8KB of space, provided the sector security status (SSS) allows it. The root mode allows modification of the SSS data and other information, provided the proper password is submitted. The default password for a new tag is 0x00000000. See the datasheet for more details.

The Seeed Studio* wiki page for this device includes a link to an Android* application that can be used to also read and write the device via NFC, as well as set NFC passwords, which cannot be done via I2C.

    // Instantiate an M24LR64E on I2C bus 0

    upm::M24LR64E nfcTag(M24LR64E_I2C_BUS);

    // This example accesses the device in the 'user' (default) mode,
    // reads the last byte of data in the EEPROM, inverts it, writes
    // it back, and then re-reads it.

    // Read the last byte of the EEPROM area

    int addr = M24LR64E::EEPROM_I2C_LENGTH - 1;
    printf("Address: %d\n", addr);
    uint8_t byte = nfcTag.readByte(addr);
    printf("Read byte: %02x\n", byte);

    // Now change it to it's opposite and write it
    byte = ~byte;
    nfcTag.writeByte(addr, byte);
    printf("Wrote inverted byte: %02x\n", byte);

    // Now read it back.
    byte = nfcTag.readByte(addr);
    printf("Read byte: %02x\n", byte);

Public Types
enum	M24LR64E_ADDR_T {   I2C_PASSWORD_ADDR = 2304, RF_PASSWORD_1_ADDR = 2308, RF_PASSWORD_2_ADDR = 2312, RF_PASSWORD_3_ADDR = 2316,   DSFID_ADDR = 2320, AFI_ADDR = 2321, RESV_ADDR = 2322, CONFIG_ADDR = 2323,   UID_ADDR = 2324, MEM_SIZE_ADDR = 2332, IC_REF_ADDR = 2335, PROG_COMP_ENERGY_HARVEST_ADDR = 2339 }
enum	AccessMode { USER_MODE = 0x0, ROOT_MODE = 0x1 }
enum	SectorAccessRight { Access_1110 = 0, Access_1111 = 1, Access_1100 = 2, Access_0111 = 3 }
enum	SectorSelectPassWd { noPasswd = 0, passwd_1 = 1, passwd_2 = 2, passwd_3 = 3 }

Public Member Functions
	M24LR64E (int bus, AccessMode mode=USER_MODE)
	~M24LR64E ()
bool	submitPasswd (uint32_t passwd)
bool	writePasswd (uint32_t passwd)
void	sectorProtectConfig (unsigned int sectorNumber, bool protectEnable, SectorAccessRight accessRight, SectorSelectPassWd passwd)
void	clearSectorProtect (void)
void	sectorWriteLockBit (unsigned int sectorNumber, bool sockEnable)
uint8_t	getDSFID ()
uint8_t	getAFI ()
uint8_t *	getUID ()
uint32_t	getMemorySize ()
void	clearMemory ()
mraa::Result	writeByte (unsigned int address, uint8_t data)
mraa::Result	writeBytes (unsigned int address, uint8_t *buffer, int len)
uint8_t	readByte (unsigned int address)
int	readBytes (unsigned int address, uint8_t *buffer, int len)

Static Public Attributes
static const int	EEPROM_I2C_LENGTH = 8192
static const int	PASSWORD_LENGTH = 4
static const int	SECTOR_SECURITY_STATUS_BASE_ADDR = 0x800
static const uint8_t	LOCK_PROTECT_BIT = 0x01
static const uint8_t	WRITE_READ_PROTECT_BIT = 0x02
static const uint8_t	PASSWORD_CTRL_BIT = 0x04
static const int	UID_LENGTH = 8
static const unsigned int	I2C_WRITE_TIME = 5

Protected Member Functions
mraa::Result	EEPROM_Write_Byte (unsigned int address, uint8_t data)
mraa::Result	EEPROM_Write_Bytes (unsigned int address, uint8_t *data, int len)
uint8_t	EEPROM_Read_Byte (unsigned int address)
int	EEPROM_Read_Bytes (unsigned int address, uint8_t *buffer, int len)

Protected Attributes
mraa::I2c	m_i2c

Member Enumeration Documentation

enum M24LR64E_ADDR_T

M24LR64E addresses, accessible only in the root mode

Constructor & Destructor Documentation

M24LR64E	(	int	bus,
		AccessMode	mode = USER_MODE
	)

M24LR64E constructor

Parameters

bus	I2C bus to use
mode	Access mode (user or root) to use

~M24LR64E

(

)

M24LR64E destructor

Member Function Documentation

bool submitPasswd

(

uint32_t

passwd

)

Submits an I2C access password

Parameters

passwd

4-byte access password

bool writePasswd

(

uint32_t

passwd

)

Writes a new I2C password

Parameters

passwd

4-byte access password

void sectorProtectConfig	(	unsigned int	sectorNumber,
		bool	protectEnable,
		SectorAccessRight	accessRight,
		SectorSelectPassWd	passwd
	)

Sets a protection bit for a sector. Must be in the root mode

Parameters

sectorNumber	Sector whose protection you are modifying
protectEnable	True if you are enabling protection
accessRight	Access rights to set
passwd	Password number to enable, if any

void clearSectorProtect

(

void

)

Clears sector protection bits. Must be in the root mode.

void sectorWriteLockBit	(	unsigned int	sectorNumber,
		bool	sockEnable
	)

Sets or clears a sector security status lock bit for a sector. Must be in the root mode.

Parameters

sectorNumber	Sector whose SSS you want to modify
sockEnable	True to set the bit, false to clear it

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uint8_t getDSFID

(

)

Returns a data storage family identifier (DSFID) Must be in the root mode.

Returns

DSFID

uint8_t getAFI

(

)

Returns an application family identifier (AFI) Must be in the root mode.

Returns

AFI

uint8_t * getUID

(

)

Returns a unique ID. Must be in the root mode. Maintained to preserve compatibility with older code.

Returns

buf Buffer to hold the UID. Must be UID_LENGTH bytes.

uint32_t getMemorySize

(

)

Returns the memory size Must be in the root mode.

Returns

Amount of memory present

void clearMemory

(

)

Sets all memory to 0, if permissions allow

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mraa::Result writeByte	(	unsigned int	address,
		uint8_t	data
	)

Writes a byte to the EEPROM

Parameters

address	Address to write to
data	Data to write

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mraa::Result writeBytes	(	unsigned int	address,
		uint8_t *	buffer,
		int	len
	)

Writes bytes to the EEPROM

Parameters

address	Address to write to
buffer	Data to write
len	Length of the data buffer

uint8_t readByte

(

unsigned int

address

)

Reads a byte from the EEPROM

Parameters

address

Address to read from

Returns

data Value read

int readBytes	(	unsigned int	address,
		uint8_t *	buffer,
		int	len
	)

Reads multiple bytes from the EEPROM

Parameters

address	Address to read from
buffer	Buffer to store data
len	Number of bytes to read

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The documentation for this class was generated from the following files:

• src/m24lr64e/m24lr64e.hpp
• src/m24lr64e/m24lr64e.cxx