How to use "NFC Tap" -> "CoreNFC" -> "Custom"

[JDirk.1]

I thought I could send custom commands to the ST25DV Tag by using the NFC Tap app. Is that possible?

In the app there are two fields when I chose "Custom":

1) Custom Command. There I enter "AC", to Read Message (mailbox).

2) Data: what to enter here?

Can someone explain how to use it? I send some bytes to the mailbox by i2C and now I want to use the app (NFC Tap) to read these bytes.

Navigation inside the app: "NFC Tap" -> "CoreNFC" -> "Custom"

[France Berthelot]

Hello

You have to build the command according to the Databrief, to simplify, you have to use and setup following parameters:

Request parameters:

• Request flag

• UID (Optional)

• Pointer (start at 00h)

• Number of bytes is one less then the requested data

Please refers to datasheet on st.com for parameters details

ST25DV16KC - Dynamic NFC/RFID tag IC with 16-Kbit EEPROM, and fast transfer mode capability - STMicroelectronics page 123 for exemple.

Before reading the message, you probably need to know how many bytes are available, you can use Read message Length command ...

For exemple, the following custom cmd, read mailbox, if a message has previously been posted...

Hope this will help, building customs cmds.

BR, FB

[JDirk.1]

Thank you very much for your fast reply. My app looks very different from yours, please see attached.

What kind of app is shown in your message?

[France Berthelot]

Hello

Android apps, but you are working with the iOS one, you should probably have a menu just before CoreNFC one with Custom Commands which is similar to the android one.

Nevertheless, it is the same way of doing you should provide correct full command data applicable to the context and command description provided in the Datasheet.

BR,FB

[JDirk.1]

Hi, could you guide me where to find it, I am attaching a screen shot from the menu before CoreNFC. In case my previous posted screenshot is the right location, could you please tell me what to enter under Custom Command and Data to read the mailbox in case a message was placed there?

[JDirk.1]

... just tried command 0xAA to write a message. Its working.

Command: AA

Data: 010908 (01 = 2 bytes; first byte 09 and second byte 08).

Any hint why the read command doesn't work?

Command: AC

Data: 0000 (MBpointer to 00 and Number of Bytes to 00 -> MB_LEN bytes should be returned)

Feedback: custom : OK

I was expecting to see the 4 bytes I placed by i2C to the tag but instead I get the feedback: custom : OK what does that mean?

[France Berthelot · Accepted solution]

Hello

Apologize for delay, but we have released a new version in which you have the UI I told to you.

Please refers to this UI, it will provides more details information in order to build commands. Refers also to datasheet for commands parameters and errors returned if any.

BR,FB

[JDirk.1]

Hello,

I checked it out and it is working fine! Many thanks for your quick support. It helps a lot to use the ST25DV tag in my future products.