ST25DV16K: Wrong data for Fast Extended Read Multiple Blocks

[michaelneeser9]

Hello,

I' am using a ST25DV16K transponder. If a Fast Read command is executed with a block number > 255, the tag does not respond with the correct content. The tag seems to evaluate only the low byte of the address. For address 256 (0x0100) the content of address 0x00 is transmitted.

Is it an error of the tag or am I doing something wrong ?

Best regards

Michael

[JL. Lebon]

​Dear Michael,

Can you please send the exact hexadecimal content of your command  request ?

Best regards.

[michaelneeser9]

Hello,

I send a "Fast Extended Read Single Block" in addressed Mode. UID is E0 02 26 00 03 23 19 43

Complete Command: 22 C4 02 43 19 23 03 00 26 02 E0 00 01 4D 20

The tag answers with data from block 0

If I send a "Extended Read Single Block" the tag answers with the correct data (block 256)

Complete Command: 22 30 43 19 23 03 00 26 02 E0 00 01 B2 DC

Best regards

Michael

[JL. Lebon · Accepted solution]

Hello,

It is recommended to use the Fast Extended Read Multiple Blocks command (C5h) instead of the Fast Extended Read Single Block command (C4h),

If desired, you can get exactly the same functionality than the single block command by setting the number of blocks to read to 0 (only one block read).

So the command 22 C4 02 43 19 23 03 00 26 02 E0 00 01 4D 20 becomes 22 C5 02 43 19 23 03 00 26 02 E0 00 00 00 01 E4 ED

Best regards.