Skip to main content
I
itsgimbi
Visitor II
December 11, 2023
Solved

ST25R3911B-DISCO Data Buffer Size

  • December 11, 2023
  • 1 reply
  • 768 views

At the moment, I am using the default firmware on the ST25R3911B-DISCO and have been reading and writing to a ST25DV04K tag. I know that the ST25DV04K tag supports a size of a 256-byte buffer, but I am wondering if the ST25R3911B does as well. If it does, what would I need to change in the firmware?

    This topic has been closed for replies.
    Best answer by Ulysses HERNIOSUS

    Hi itsgimbi,

    NFC-V in ST25R3911B is not directly supported, for receiving the Manchester stream needs to be decoded in software. So using 255 bytes of payload requires approximately 520 bytes of Manchester stream. 

    ST25R3911B has a FIFO of 96 bytes.

    This means software/rfalWorker has to run fast enough to be able to empty FIFO before overrunning and that the buffer used for reception needs to be big enough to hold these ~520 bytes. In our typical demos this is granted (rfalNfcvWorkingData.codingBuffer is big enough) and rfalWorker() is called frequently enough.

     

     

    Best Regards, Ulysses

    1 reply

    U
    Ulysses HERNIOSUSAnswer
    Technical Moderator
    December 12, 2023

    Hi itsgimbi,

    NFC-V in ST25R3911B is not directly supported, for receiving the Manchester stream needs to be decoded in software. So using 255 bytes of payload requires approximately 520 bytes of Manchester stream. 

    ST25R3911B has a FIFO of 96 bytes.

    This means software/rfalWorker has to run fast enough to be able to empty FIFO before overrunning and that the buffer used for reception needs to be big enough to hold these ~520 bytes. In our typical demos this is granted (rfalNfcvWorkingData.codingBuffer is big enough) and rfalWorker() is called frequently enough.

     

     

    Best Regards, Ulysses

    Terms & ConditionsAccessibility statement