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Issue with I2C communication with ST25DV64KC tag

PoolBear
Associate III

Hi @Rene Lenerve  @JL. Lebon  @Brian TIDAL 

So basically I am connecting ST25DV64KC tag with MKE14F512VLL16 based controller and I want to write on the tag through i2c but as I am sending data using I2c write and as I am checking using Logic analyzer it showing its writing and sending ack but when I am checking using st nfc tap app  options read memory  there nothing was written can you guys confirm few things like is tag slave  device address  is 0xA6  for writing on tag and is it mandatory to give memory address or it will assume 0000h as base address and write on it  and to write on tag do we need to send one byte at a time .Can you please provide details about i2c communication to  write on tag by the way I have already gone through the datasheet.

15 REPLIES 15
PoolBear
Associate III

Hello @Rene Lenerve  @JL. Lebon  @Brian TIDAL 

I will write on the tag using I2c only so like can please provide the register number and like how to do it using i2c 

Hi, 

Not sure to understand what you want to do.
Do you want to change password from I2C interface? Be aware that RF password can only be presented and changed from the RF interface, and I2C password can only be presented and changed from the I2C interface. There is no bridge between I2C and RF regarding passwords.

Best regards.

PoolBear
Associate III

Hello @Rene Lenerve  @JL. Lebon  @Brian TIDAL

so as I have locked the RFA1SS(0004h) now when I am going to write on area 1 its asking for passwords which is by default zero so any one can write on area 1  using this st app so I want to change this RFA1SS passwords to write but don't want to use RF as medium to write only want send data through i2c from my controller to tag to change this passwords .

Hi, 

Ok. Unfortunately, as I said in my previous post, you cannot change any RF password from the I2C interface. The only way is using the RF command Write Password.

Best reagrds.

PoolBear
Associate III

Hello @Rene Lenerve  @JL. Lebon  @Brian TIDAL

did you guys have any other tag where we can do that

JL. Lebon
ST Employee

Hello, 

Sorry for my late answer, I missed your question.
We do have the M24SR in which RF passwords can be modified from I2C interface. The M24SR is an NFC type 4 (ISO14443), so quite different from the ST25DV though.

Best regards.