Cannot send larger chuncks than 4096 bytes to ST25DV64KC

[HStee.1]

We use dev. kit: ANT7-T-ST25DV64KC with app version: ST25NFCTap version V3.7.0 / ST25SDK: 1.10.0 public version. Q: I try to write binary data from file to it. I succeed in sending 4096 bytes. But when I try to send larger files it fails (tried 8192 bytes) with the error message:

Error while writing data:

com.st.st25sdk.STException: Error BAD_PARAMETER

Q: Is this a known issue or am I doing something wrong?

[HStee.1 · Accepted solution]

After doing some reading/writing tests over I2C I found the "problem" myself. The NFC tag concerned is of size 64k BITS. For some reasons (bad reading) I assumed 64k bytes. 64kbits results in 8kbytes and that is exactly what I can read/write to it.

[Tesla DeLorean]

FLASH and EEPROM memories have historically been quoted in BITs as this directly drives the size and number of transistors in the memory array.

The byte/word formats tend to be on the interface side, and can also vary widely, ie 4, 8, 16, 32, etc. With arrays within SoC the bus/line widths can also be significantly bigger as the bus doesn't need to be exported to pins on a package. On STM32 devices the array's are frequently 64 or 128-bit wide, so the initial fetch is quite expensive, but subsequent bytes are immediately available (zero time)