How to receive more than 255 bytes of data via the fast transfer mailbox using the android St25 sdk?

[KRa.1]

Hi,

I am attempting to receive a large amount of information via fast transfer mailbox on a ST25DV64K chip and and AndroidNFCReader using one mST25DVTag.writeMailboxMessage command, which commands the chip to send data continuously so long as it receives an Ack that the 255 bytes from one message has been read (via .readMailboxMessage).

I can successfully receive the first message containing the first 255 bytes, however I am unsure how to advise the chip that the data has been read (i.e. an Ack of sorts) and to send the next block of data. At the moment the output repeats the first 255 bytes when in a while loop with a time delay (as can be seen below), so I am just wondering, if I need to receive more data would anyone be able to advise on the command to use to ensure this happens.

Kind Regards,

[France Berthelot · Accepted solution]

​Hello

Regarding your log, I saw that you :

• Write a message from RF to Tag Mailbox
• Read message from RF to Tag Mailbox - pointer = 0 length = 0 ==> full mailbox to be read / Mailbox register flag status will be updated automatically as all message read.

Read again from RF to Tag Mailbox full message = new content appears, probably put from i2C

.....

Read again from RF to Tag Mailbox full message every 50ms ....

You need on FW to put in place interruption on GPO to know that RF has read message (see ST25DV DS) and then write again (this avoid conflicting access on both side)

On RF side you need to check the MB status byte which gives you informations on Mailbox status (RF put message, I2C put message, ....) . According to this if i2C put message, you read it from RF with readMessage.

You can repeat this until the end of data to be sent.

You have some materials (code/ exemples/...) that demonstrate this feature on www.st.com

Android application :https://www.st.com/content/st_com/en/products/embedded-software/st25-nfc-rfid-software/stsw-st25001.htmlsearch for ... (provide exemples of FW update, image transfert, Mailbox status,...) using ST25SDK  -  search for ST25DVTransferTask, ST25DVPictureTransferDemoActivity, ST25DVFirmwareUpdateDemoActivity, ...

Product DS : https://www.st.com/resource/en/datasheet/st25dv04k.pdf

User Manual for Discovry kit and demos : https://www.st.com/content/st_com/en/products/embedded-software/st25-nfc-rfid-software/stsw-st25dv001.html

I hope these informations will help understanding you exchange issue.

BR

[KRa.1]

Thanks for the help.