[M24SR64-Y] CC File write access field issue

[pa0grg]

Hello,

i'm experiencing issues on M24SR64-Y chip. In fact, i can't write any record neither via RF or I2C. 

Until this morning (for weeks, actually) i was working fine, capable of writing whatever record i wanted to either via RF and I2C. Suddenly, it stopped working (NFC Tools android application returned "Writing error" warning). In the attachements you will find the CC Buffer from my chip. In particular, the 15th element (Write Access) field is set on 0xFE value. According to M24SR64's datasheet, there's no value 0xFE state but: 0x00 (Write access without any security), 0x80 (Locked), 0xFF (write not authorized).

The tag is actually readable, and NFC Tools displays these infos: "Readable only: no", "Writeable: no".

What do you suggest me to do?

[Brian TIDAL]

Hi,

can you provide a hex dump of the CC file? I would guess that 0xFE is the Read Access value. In that case, it is likely that the NDEF File has been permanently locked.

Rgds

BT

[pa0grg]

In the attachements:

CC_File_HexDump: data read in hex format
CC_File: CC File read (decimal)
M24SR_Init: call stack to read CC File

Thanks.

[Brian TIDAL]

Hi,

What you show is the content of a decoding structure that can be erroneous (wrong decoding or data corrupted). Can you share the raw result of the read file command (this can be a logic analyzer trace of the I2C) ? 

Rgds

BT