Why can't ST25 read sensor data？

[Schuyler]

float K_Temperature ; //K型热电偶 温度值
char temperaturebuffer[30] = { 0xD1, 0x01, 0x1B, 0x54, 0x02, 0x65, 0x6E };
uint16_t TarAddr= 0x0000;  
/* Write NDEF to EEPROM */
	  K_Temperature=MAX6675_ReadTemperature(); //读取热电偶温度值
	  sprintf(&temperaturebuffer[7], "Temperature: %.2f C", K_Temperature);
	  NFC07A1_NFCTAG_WriteData(NFC07A1_NFCTAG_INSTANCE, (uint8_t *)temperaturebuffer, TarAddr, strlen(temperaturebuffer) + 1);
	  uint8_t ReadData[30];
	  NFC07A1_NFCTAG_ReadData(NFC07A1_NFCTAG_INSTANCE, ReadData, TarAddr, sizeof(ReadData));
	  // 延时一段时间
	  HAL_Delay(300);
	  NFC07A1_LED_On( GREEN_LED );

I converted the temperature data into a string and wrote it to the address, but NFC couldn't get the temperature information. I don't know if it's a write function usage error or a write address error, but here's what NFC gets.

[Brian TIDAL]

Hi,

see the first reply of https://community.st.com/t5/st25-nfc-rfid-tags-and-readers/x-cube-nfc7-no-ndef-seen-by-the-phone/td-p/144185: NFC07A1_NFCTAG_WriteData writes raw data into the tag and therefore this is not NDEF formatted. 

Rgds

BT

[Schuyler]

Hi @Brian TIDAL 

But what I am writing is sensor data, which is dynamic data. Can I follow the above reference? Is there a specific method for writing NFC into sensors?

[Brian TIDAL]

HI,

I've just seen that temperaturebuffer contains an NDEF TEXT record header (D1 01 etc.). So I assume you write the temperature value inside a TEXT record. But as TarAddr  equals 0, this NDEF is written by NFC07A1_NFCTAG_WriteData at block 0 whereas block 0 should contain the NFC Forum Capability Container. Therefore the tag is no longer properly formatted. 

I would suggest to reuse X-CUBE-NFC7\1.0.0\Projects\NUCLEO-L476RG\Applications\NDEF_URI in your application and to modify it to use a TEXT record instead of an URI record.

If you still prefer to use NFC07A1_NFCTAG_WriteData, make sure to have a Capability container in block 0 and the NDEF Type and Length fields before the NDEF TEXT record.

Rgds

BT

[Schuyler]

Hi @Brian TIDAL 

I tried using NfcTag_ WriteNDEF can display temperature data correctly in text form, but I am currently debugging STEVAL-SMARTAG1, and the code does not include NDEF related function definitions, only NFCTAG_ WriteData and NFCTAG_ ReadData, do you have any suggestions for me to try to read temperature data?

[Brian TIDAL · Accepted solution]

Hi,

if your application is supposed to write the temperature data as a TEXT NDEF record, the tag has to be properly NDEF formatted (i.e. with a Capability Container starting at block 0 followed by an NDEF TLV). See 

AN4911 (NDEF management with ST25DV-I2C Series, and ST25TV16K and ST25TV64K products) for detailed information.

Rgds

BT

[Schuyler]

Hi @Brian TIDAL 

Thank you for your answer. According to the instructions of AN4911, I can only know the theoretical knowledge of NDEF, but I currently need to read the dynamic temperature data without code instructions, how should I deal with K_Temperature in the software design?

K_Temperature=MAX6675_ReadTemperature(); // Read the thermocouple temperature value.

[Brian TIDAL]

Hi,

I am sorry but I do not understand your last post. I am afraid I cannot help more.

Rgds

BT

[Schuyler]

Hi @Brian TIDAL 

I know the  Capability Container starting at block 0 followed by an NDEF TLV, I change the write address to 0XD1, which is block 01:03 11 D1 01: NDEF TLV (T=03h, L=11h,), can the following corrected code write temperature data correctly?

float K_Temperature ; 
char temperaturebuffer[30] = { 0xD1, 0x01, 0x1B, 0x54, 0x02, 0x65, 0x6E };
uint16_t TarAddr= 0xD1;
void MX_NFC7_NDEF_URI_Init(void)
{
	  /******************************************************************************/
  /* Configuration of X-NUCLEO-NFC02A1                                          */
  /******************************************************************************/
  /* Init of the Leds on X-NUCLEO-NFC07A1 board */
  NFC07A1_LED_Init(GREEN_LED );
  NFC07A1_LED_Init(BLUE_LED );
  NFC07A1_LED_Init(YELLOW_LED );
  NFC07A1_LED_On( GREEN_LED );
  HAL_Delay( 300 );
  NFC07A1_LED_On( BLUE_LED );
  HAL_Delay( 300 );
  NFC07A1_LED_On( YELLOW_LED );
  HAL_Delay( 300 );

  /* Init ST25DVXXKC driver */
  while( NFC07A1_NFCTAG_Init(NFC07A1_NFCTAG_INSTANCE) != NFCTAG_OK );

  /* Reset Mailbox enable to allow write to EEPROM */
  NFC07A1_NFCTAG_ResetMBEN_Dyn(NFC07A1_NFCTAG_INSTANCE);

  NfcTag_SelectProtocol(NFCTAG_TYPE5);

  /* Check if no NDEF detected, init mem in Tag Type 5 */
  if( NfcType5_NDEFDetection( ) != NDEF_OK )
  {
    CCFileStruct.MagicNumber = NFCT5_MAGICNUMBER_E1_CCFILE;
    CCFileStruct.Version = NFCT5_VERSION_V1_0;
    CCFileStruct.MemorySize = ( ST25DVXXKC_MAX_SIZE / 8 ) & 0xFF;
    CCFileStruct.TT5Tag = 0x05;
    /* Init of the Type Tag 5 component (M24LR) */
    while( NfcType5_TT5Init( ) != NFCTAG_OK );
  }

  /* Init done */
  NFC07A1_LED_Off( GREEN_LED );
  HAL_Delay( 300 );
  NFC07A1_LED_Off( BLUE_LED );
  HAL_Delay( 300 );
  NFC07A1_LED_Off( YELLOW_LED );
  HAL_Delay( 300 );

}

/**
  * @brief  Process of the NDEF_URI application
  * @retval None
  */
void MX_NFC7_NDEF_URI_Process(void)
{
	  /* Write NDEF to EEPROM */
	  K_Temperature=MAX6675_ReadTemperature(); 
	  sprintf(&temperaturebuffer[7], "Temperature: %.2f C", K_Temperature);
	  NFC07A1_NFCTAG_WriteData(NFC07A1_NFCTAG_INSTANCE, (uint8_t *)temperaturebuffer, TarAddr, strlen(temperaturebuffer) + 1);
	  uint8_t ReadData[NFCTAG_64K_SIZE];
	  NFC07A1_NFCTAG_ReadData(NFC07A1_NFCTAG_INSTANCE, ReadData, TarAddr, strlen(temperaturebuffer) + 1);
	  HAL_Delay(300);
	  NFC07A1_LED_On( GREEN_LED );
}