Extended Read Multiple Blocks (Android NfcV)

[DMugg.1]

I need to read multiple blocks of the ST25DV64K-I.

For example 178 Blocks starting from 1D.

UID: E0 02 26 00 A7 3B 33 B6

My command:

22 33 B6 33 3B A7 00 26 02 E0 1D B2

I only get 01:02.

What's wrong with my command?

[Brian TIDAL · Accepted solution]

Hi,

the proper coding of the Extended read Multiple Blocks is:

• request flags: 8 bits
• 33h
• UID( when address_flag = 1): 64 bits
• first block number: 16 bits
• Number of blocks: 16 bits

So, 2 bytes are missing in your command.

Rgds

BT

[DMugg.1]

Oh right of course so it gets: 22 33 B6 33 3B A7 00 26 02 E0 1D 00 B2 00

The maximum Blocks should be 2047? But I can't read my 178 Blocks.

I now just get the I/O failure...

Thanks for your help.

DM

[Brian TIDAL]

Hi,

can you share more information about the I/O failure? Android failure or tag failure?

I don't know the physical limits on Android when transceiving NFC data and that may be the cause of this failure. What about sending 6 x Extended Read Multiple blocks (32 blocks)?

Rgds

BT

[DMugg.1]

You are right...

The limit is 64 as it seems.

65 number of Blocks just get rejected...

[Brian TIDAL]

Hi

this limit is an Android limit.

ST25DV64K-I accepts up to NumOfBlocks=2047.

Rgds

BT

[DMugg.1]

Yea that's kinda sad..

So I have to make multiple requests for the same number of blocks...