Write to system configuration area on ST25

[David_Wallis]

I am trying to write to the configuration area of an ST25DV04KC NFC chip using I2C. I am able to read and write to the user area. I am able to present the default password (8 zeros, 0x09, 8 zeros) and the SSO_Dyn register switches from 0x00 to 0x01, indicating that I have entered a secure session. It also switches back to 0x00 if I present a bad password.

With the SSO_Dyn register reading 0x01, I then write with addressing 0xAE the following bytes: 0x00, 0x05, 0x08. The message doesn't receive an ACK and the value doesn't change. I can read and write everything OK using the ST25 tap app on my phone. I am also able to read the configuration registers over I2C. A dump of my configuration registers taken over I2C is below.

What could I be doing wrong?

Thanks,

David

CFG: 0x0000: 0x11
CFG: 0x0001: 0x0c
CFG: 0x0002: 0x01
CFG: 0x0003: 0x00
CFG: 0x0004: 0x00
CFG: 0x0005: 0x04
CFG: 0x0006: 0x00
CFG: 0x0007: 0x07
CFG: 0x0008: 0x00
CFG: 0x0009: 0x0c
CFG: 0x000a: 0x00
CFG: 0x000b: 0x00
CFG: 0x000c: 0x00
CFG: 0x000d: 0x00
CFG: 0x000e: 0x1a
CFG: 0x000f: 0x00
CFG: 0x0010: 0x00
CFG: 0x0011: 0x00
CFG: 0x0012: 0x00
CFG: 0x0013: 0x00
CFG: 0x0014: 0x7f
CFG: 0x0015: 0x00
CFG: 0x0016: 0x03

[JL. Lebon]

Hello David,

All you do seems correct. Can you post the exact I2C command you are sending, just to check that it is good? (all the Bytes that are sent to the ST25DV). Also, do you know at which Byte the ACK is not received?

Best regards.