API Reference for the SFE_ST25DV64KC_NDEF class

Brief Overview

The SFE_ST25DV64KC_NDEF class provides additional methods to read and write NDEF (NFC Forum Data Exchange Format) records from EEPROM memory. The SFE_ST25DV64KC_NDEF class inherits all of the methods of the SFE_ST25DV64KC class.

Capability Container Methods

writeCCFile4Byte()

This method will write a 4-byte Capability Container file to the first 4 bytes of EEPROM memory.

Note

This method is only useful for small tags like the ST25DV04KC. The ST25DV64KC requires an 8-byte CC file.

bool writeCCFile4Byte(uint32_t val)

Parameter	Type	Description
`val`	`uint32_t`	The 32-bit (4-byte) capability container. Default is 0xE1403F00
return value	`bool`	`true` is the write was successful, otherwise `false`

writeCCFile8Byte()

This method will write a 8-byte Capability Container file to the first 8 bytes of EEPROM memory.

bool writeCCFile8Byte(uint32_t val1, uint32_t val2)

Parameter	Type	Description
`val1`	`uint32_t`	The first 32-bits (4-bytes) of the capability container. Default is 0xE2400001
`val2`	`uint32_t`	The second 32-bits (4-bytes) of the capability container. Default is 0x000003FF
return value	`bool`	`true` is the write was successful, otherwise `false`

setCCFileLen()

This method allows the _ccFileLen member variable to be manually updated if required.

_ccFileLen has a default value of 8 (for the ST25DV64KC).

_ccFileLen is automatically set to 4 when writeCCFile4Byte is called. _ccFileLen is automatically set to 8 when writeCCFile8Byte is called.

void setCCFileLen(uint16_t newLen)

Parameter	Type	Description
`newLen`	`uint16_t`	The new value for `_ccFileLen`

getCCFileLen()

This method returns the current value of _ccFileLen. It returns the correct start address to be passed to the writeNDEF functions.

uint16_t getCCFileLen()

Parameter	Type	Description
return value	`uint16_t`	The current value of `_ccFileLen`

NDEF Methods

writeNDEFEmpty()

This method writes an empty (zero-length) NDEF record to EEPROM. It can be useful to call this after clearing the EEPROM memory and writing the CC File. This allows the smart phone App to read the NDEF file - even though it is empty.

bool SFE_ST25DV64KC_NDEF::writeNDEFEmpty(uint16_t *address)

Parameter	Type	Description
`address`	`uint16_t *`	A pointer to a `uint16_t` containing the start address for this record. Default is `NULL`. If not provided, the record is written to `_ccFileLen`
return value	`bool`	`true` if the write was successful, otherwise `false`

writeNDEFURI()

This method writes an NDEF URI record to EEPROM.

The URI is passed in uri.

Setting idCode to the appropriate ID Code will save memory. The URI prefix (e.g. https://www. ) is then stored as a single byte.

Multiple records can be written by: providing an address plus Message Begin (MB) and Message End (ME) flags.

If address is provided, it is updated with the memory location after the final one written as part of this record. This allows it to be used as the start address for the next record.

A single record has both MB and ME flags set true.

The TLV T and L fields are set automatically. The L field is updated from 1-byte to 3-byte automatically if the new record takes the total length beyond 254 bytes.

bool writeNDEFURI(const char *uri, uint8_t idCode, uint16_t *address, bool MB, bool ME)

Possible values for idCode are:

#define SFE_ST25DV_NDEF_URI_ID_CODE_NONE 0x00
#define SFE_ST25DV_NDEF_URI_ID_CODE_HTTP_WWW 0x01
#define SFE_ST25DV_NDEF_URI_ID_CODE_HTTPS_WWW 0x02
#define SFE_ST25DV_NDEF_URI_ID_CODE_HTTP 0x03
#define SFE_ST25DV_NDEF_URI_ID_CODE_HTTPS 0x04
#define SFE_ST25DV_NDEF_URI_ID_CODE_TEL 0x05
#define SFE_ST25DV_NDEF_URI_ID_CODE_MAILTO 0x06
#define SFE_ST25DV_NDEF_URI_ID_CODE_FTP_ANON_ANON 0x07
#define SFE_ST25DV_NDEF_URI_ID_CODE_FTP_FTP 0x08
#define SFE_ST25DV_NDEF_URI_ID_CODE_FTPS 0x09
#define SFE_ST25DV_NDEF_URI_ID_CODE_SFTP 0x0A
#define SFE_ST25DV_NDEF_URI_ID_CODE_SMB 0x0B
#define SFE_ST25DV_NDEF_URI_ID_CODE_NFS 0x0C
#define SFE_ST25DV_NDEF_URI_ID_CODE_FTP 0x0D
#define SFE_ST25DV_NDEF_URI_ID_CODE_DAV 0x0E
#define SFE_ST25DV_NDEF_URI_ID_CODE_NEWS 0x0F
#define SFE_ST25DV_NDEF_URI_ID_CODE_TELNET 0x10
#define SFE_ST25DV_NDEF_URI_ID_CODE_IMAP 0x11
#define SFE_ST25DV_NDEF_URI_ID_CODE_RTSP 0x12
#define SFE_ST25DV_NDEF_URI_ID_CODE_URN 0x13
#define SFE_ST25DV_NDEF_URI_ID_CODE_POP 0x14
#define SFE_ST25DV_NDEF_URI_ID_CODE_SIP 0x15
#define SFE_ST25DV_NDEF_URI_ID_CODE_SIPS 0x16
#define SFE_ST25DV_NDEF_URI_ID_CODE_TFTP 0x17
#define SFE_ST25DV_NDEF_URI_ID_CODE_BTSPP 0x18
#define SFE_ST25DV_NDEF_URI_ID_CODE_BTL2CAP 0x19
#define SFE_ST25DV_NDEF_URI_ID_CODE_BTGOEP 0x1A
#define SFE_ST25DV_NDEF_URI_ID_CODE_TCPOBEX 0x1B
#define SFE_ST25DV_NDEF_URI_ID_CODE_IRDAOBEX 0x1C
#define SFE_ST25DV_NDEF_URI_ID_CODE_FILE 0x1D
#define SFE_ST25DV_NDEF_URI_ID_CODE_URN_EPC_ID 0x1E
#define SFE_ST25DV_NDEF_URI_ID_CODE_URN_EPC_TAG 0x1F
#define SFE_ST25DV_NDEF_URI_ID_CODE_URN_EPC_PAT 0x20
#define SFE_ST25DV_NDEF_URI_ID_CODE_URN_EPC_RAW 0x21
#define SFE_ST25DV_NDEF_URI_ID_CODE_URN_EPC 0x22
#define SFE_ST25DV_NDEF_URI_ID_CODE_URN_NFC 0x23

Parameter	Type	Description
`uri`	`const char *`	A pointer to the URI
`idCode`	`uint8_t`	The URI prefix. `SFE_ST25DV_NDEF_URI_ID_CODE_HTTPS_WWW` = `https://www.` etc.. Default is `SFE_ST25DV_NDEF_URI_ID_CODE_NONE`
`address`	`uint16_t *`	A pointer to a `uint16_t` containing the start address for this record. Default is `NULL`. If not provided, the record is written to `_ccFileLen`
`MB`	`bool`	Message Begin flag. Default is `true`
`ME`	`bool`	Message End flag. Default is `true`
return value	`bool`	`true` if the write was successful, otherwise `false`

readNDEFURI()

This method reads and returns a single NDEF URI from EEPROM.

By default, the first record is returned. The second and subsequent records can be read by setting recordNo to the desired value.

If the chosen recordNo is not present, the method returns false. This provides an easy way to count the number of URIs in memory.

bool readNDEFURI(char *theURI, uint16_t maxURILen, uint8_t recordNo)

Parameter	Type	Description
`theURI`	`char *`	A pointer to the char array which will hold the URI
`maxURILen`	`uint16_t`	The maximum number of bytes which `theURI` can hold. I.e. the `sizeof` of `theURI`
`recordNo`	`uint8_t`	The URI record to be read. Default is 1
return value	`bool`	`true` if the read is successful (i.e. `recordNo` exists), `false` otherwise

writeNDEFWiFi()

This method writes an NDEF WiFi record to EEPROM.

The WiFi SSID and Password are passed in ssid and passwd.

Multiple records can be written by: providing an address plus Message Begin (MB) and Message End (ME) flags.

If address is provided, it is updated with the memory location after the final one written as part of this record. This allows it to be used as the start address for the next record.

A single record has both MB and ME flags set true.

The TLV T and L fields are set automatically. The L field is updated from 1-byte to 3-byte automatically if the new record takes the total length beyond 254 bytes.

auth (the WiFi authentication) defaults to SFE_ST25DV_WIFI_AUTH_WPA2_PERSONAL, as specified by the Wi-Fi Simple Configuration Technical Specification.

encrypt (the WiFi encryption) defaults to SFE_ST25DV_WIFI_ENCRYPT_AES, as specified by the Wi-Fi Simple Configuration Technical Specification.

bool writeNDEFWiFi(const char *ssid, const char *passwd, uint16_t *address, bool MB, bool ME, const uint8_t auth[2], const uint8_t encrypt[2])

Possible values for auth and encrypt are:

static const uint8_t SFE_ST25DV_WIFI_AUTH_OPEN[2] = {0x00, 0x01};
static const uint8_t SFE_ST25DV_WIFI_AUTH_WPA_PERSONAL[2] = {0x00, 0x02};
static const uint8_t SFE_ST25DV_WIFI_AUTH_SHARED[2] = {0x00, 0x04};
static const uint8_t SFE_ST25DV_WIFI_AUTH_WPA_ENTERPRISE[2] = {0x00, 0x08};
static const uint8_t SFE_ST25DV_WIFI_AUTH_WPA2_ENTERPRISE[2] = {0x00, 0x10};
static const uint8_t SFE_ST25DV_WIFI_AUTH_WPA2_PERSONAL[2] = {0x00, 0x20};
static const uint8_t SFE_ST25DV_WIFI_AUTH_WPA_WPA2_PERSONAL[2] = {0x00, 0x22};

static const uint8_t SFE_ST25DV_WIFI_ENCRYPT_NONE[2] = {0x00, 0x01};
static const uint8_t SFE_ST25DV_WIFI_ENCRYPT_WEP[2] = {0x00, 0x02};
static const uint8_t SFE_ST25DV_WIFI_ENCRYPT_TKIP[2] = {0x00, 0x04};
static const uint8_t SFE_ST25DV_WIFI_ENCRYPT_AES[2] = {0x00, 0x08};
static const uint8_t SFE_ST25DV_WIFI_ENCRYPT_AES_TKIP[2] = {0x00, 0x0C};

Parameter	Type	Description
`ssid`	`const char *`	A pointer to the SSID (Network Name)
`passwd`	`const char *`	A pointer to the password (Network Key)
`address`	`uint16_t *`	A pointer to a `uint16_t` containing the start address for this record. Default is `NULL`. If not provided, the record is written to `_ccFileLen`
`MB`	`bool`	Message Begin flag. Default is `true`
`ME`	`bool`	Message End flag. Default is `true`
`auth`	`const uint8_t[2]`	The WiFi authentication method. Default is `SFE_ST25DV_WIFI_AUTH_WPA2_PERSONAL` = 0x00, 0x20
`encrypt`	`const uint8_t[2]`	The WiFi encryption method. Default is `SFE_ST25DV_WIFI_ENCRYPT_AES` = 0x00, 0x08
return value	`bool`	`true` if the write was successful, otherwise `false`

readNDEFWiFi()

This method reads and returns a single NDEF WiFi record from EEPROM.

By default, the first record is returned. The second and subsequent records can be read by setting recordNo to the desired value.

If the chosen recordNo is not present, the method returns false. This provides an easy way to count the number of WiFi records in memory.

bool readNDEFWiFi(char *ssid, uint16_t maxSsidLen, char *passwd, uint16_t maxPasswdLen, uint8_t recordNo)

Parameter	Type	Description
`ssid`	`char *`	A pointer to the char array which will hold the SSID
`maxSsidLen`	`uint16_t`	The maximum number of bytes which `ssid` can hold. I.e. the `sizeof` of `ssid`
`passwd`	`char *`	A pointer to the char array which will hold the password
`maxPasswdLen`	`uint16_t`	The maximum number of bytes which `passwd` can hold. I.e. the `sizeof` of `passwd`
`recordNo`	`uint8_t`	The URI record to be read. Default is 1
return value	`bool`	`true` if the read is successful (i.e. `recordNo` exists), `false` otherwise

writeNDEFText()

This method writes an NDEF Text record to EEPROM.

The text passed in const char *theText.

Note

The length of theText is calculated using strlen, which will fail if theText contains any zero (0x00) bytes. An overloaded method allows the text to be defined using const uint8_t *theText and uint16_t textLength if required.

The text language code can be defined using the languageCode parameter. languageCode defaults to NULL, in which case the language code is set automatically to "en" (English).

Multiple records can be written by: providing an address plus Message Begin (MB) and Message End (ME) flags.

If address is provided, it is updated with the memory location after the final one written as part of this record. This allows it to be used as the start address for the next record.

A single record has both MB and ME flags set true.

The TLV T and L fields are set automatically. The L field is updated from 1-byte to 3-byte automatically if the new record takes the total length beyond 254 bytes.

  bool writeNDEFText(const char *theText, uint16_t *address, bool MB, bool ME, const char *languageCode)
  bool writeNDEFText(const uint8_t *theText, uint16_t textLength, uint16_t *address, bool MB, bool ME, const char *languageCode)

Parameter	Type	Description
`theText`	`const char *`	A pointer to the text
`address`	`uint16_t *`	A pointer to a `uint16_t` containing the start address for this record. Default is `NULL`. If not provided, the record is written to `_ccFileLen`
`MB`	`bool`	Message Begin flag. Default is `true`
`ME`	`bool`	Message End flag. Default is `true`
`languageCode`	`const char *`	A pointer to the text language code. Default is `NULL`
return value	`bool`	`true` if the write was successful, otherwise `false`

Parameter	Type	Description
`theText`	`const uint8_t *`	A pointer to the text
`textLength`	`uint16_t`	The number of bytes contained in `theText`
`address`	`uint16_t *`	A pointer to a `uint16_t` containing the start address for this record. Default is `NULL`. If not provided, the record is written to `_ccFileLen`
`MB`	`bool`	Message Begin flag. Default is `true`
`ME`	`bool`	Message End flag. Default is `true`
`languageCode`	`const char *`	A pointer to the text language code. Default is `NULL`
return value	`bool`	`true` if the write was successful, otherwise `false`

readNDEFText()

This method reads and returns a single NDEF Text record from EEPROM.

By default, the first record is returned. The second and subsequent records can be read by setting recordNo to the desired value.

If the chosen recordNo is not present, the method returns false. This provides an easy way to count the number of WiFi records in memory.

Note

If theText could contain any zero (0x00) bytes, you can use the overloaded method to receive the actual text length. On call, set *textLen to maximum number of bytes which theText can hold. On return, *textLen will contain the actual number of chars read.

bool readNDEFText(char *theText, uint16_t maxTextLen, uint8_t recordNo, char *language, uint16_t maxLanguageLen)
bool readNDEFText(uint8_t *theText, uint16_t *textLen, uint8_t recordNo, char *language, uint16_t maxLanguageLen)

Parameter	Type	Description
`theText`	`char *`	A pointer to the char array which will hold the text
`maxTextLen`	`uint16_t`	The maximum number of bytes which `theText` can hold. I.e. the `sizeof` of `theText`
`recordNo`	`uint8_t`	The URI record to be read. Default is 1
`language`	`char *`	A pointer to the char array which could hold the language code. Default is `NULL`
`maxLanguageLen`	`uint16_t`	The maximum number of bytes which `language` can hold. I.e. the `sizeof` of `language`. Default is zero
return value	`bool`	`true` if the read is successful (i.e. `recordNo` exists), `false` otherwise

Parameter	Type	Description
`theText`	`uint8_t *`	A pointer to the array of uint8_t which will hold the text
`textLen`	`uint16_t *`	The maximum number of bytes which `theText` can hold. I.e. the `sizeof` of `theText`. On return, contains the number of bytes read
`recordNo`	`uint8_t`	The URI record to be read. Default is 1
`language`	`char *`	A pointer to the char array which could hold the language code. Default is `NULL`
`maxLanguageLen`	`uint16_t`	The maximum number of bytes which `language` can hold. I.e. the `sizeof` of `language`. Default is zero
return value	`bool`	`true` if the read is successful (i.e. `recordNo` exists), `false` otherwise

Helper Methods

getURIPrefix()

This method returns the URI prefix code at readable text. It is used by readNDEFURI to reconstruct the full URI based on the stored idCode.

const char *getURIPrefix(uint8_t prefixCode)

Parameter	Type	Description
`prefixCode`	`uint8_t`	The prefix code
return value	`const char *`	A pointer to the prefix as readable text

Member Variables

Parameter	Type	Description
`_ccFileLen`	`uint16_t`	The length of the capability container. I.e. the start address for NDEF records