How a read memory command over RF works

[dierdorf]

How a read memory command over RF works? I use the NFC Tap App and use the Read Memory command, where i can select Start Block ande Number of itmes. On the otherside i have a ST25DV64KC Tag.

The question is, do the read use the mailbox or it is possible to read directly the memory? If the mailbox is used, how the transfer from the memory works.

 

[Brian TIDAL]

Hi,

ST25DV64KC supports the READ SINGLE BLOCK and READ MULTIPLE BLOCKS  commands from the ISO 15693-3 standard. The behavior of those commands is detailled in the Datasheet of the ST25DV64KC:

"On receiving the Read Single Block command, the ST25DVxxKC reads the requested block and sends back its
32-bit value in the response"

"When receiving the Read Multiple Block command, the ST25DVxxKC reads the selected blocks and sends back
their value in multiples of 32 bits in the response."

Rgds

BT

[dierdorf]

Thanks Brian,

for me it was not clear that "Read Memory" means "Read Single Block".
I'm wondering because about the "Write Memory" command i find following in the Datasheet: "The data written in user memory (EEPROM), either from I2C or from RF, transits via the 256-Byte buffer." 

Regards

[JL. Lebon]

Hello, 
It is true that when you read or write data into EEPROM memory (user memory), it transit through the 256-Bytes buffer. But this is done automatically internally and is totally transparent to the user. 
From the user point of view (your point of view): 

- when you do a READ SINGLE BLOCK or READ MULTIPLE BLOCKS, you read data in the user memory (EEPROM)
- when you do a WRITE SINGLE BLOCK or WRITE MULTIPLE BLOCKS, you write data in the user memory (EEPROM).
That is simple as that.
Best regards.