NFC with ST25DV ISO15693 on ANDROID (kotlin)

[YazTarkann]

Hey !!

I'm new to the world of NFC, and I'm currently developing an application to communicate with a product (connected padlock) as part of my work. I know that we use mailBox for our orders. In practice, to unlock the padlock the command: 35FF1234EEEEEEEE40FFFFFFFF0000 is used. I can read the basic info: 022B, I can also read the FTM value: 02A0020D, but I can't send my order. I tried with the AA command. But nothing works, can someone help me?

Thanks in advance

[JL. Lebon]

Hello, 

In order to use the mailbox, you first need to authorize the FTM exchange and then enable the mailbox. If you have not done this yet, it won't work.

To authorize the FTM exchanges, you need to:
- first, present the RF Configuration password (password 0) -> command Present password B3h (02B302xxxxxxxxxxxxxxxx (by default password is 0000000000000000)).
- then set the bit MB_MODE=1 in the FTM configuration byte -> command Write configuration A1h (02A1020D01).  

Then to enable the mailbox, you need to write bit MB_EN=1 in the MB_CTRL_Dyn register:
- command Write Dynamic Configuration AEh (02AE020D01).

Then only you can write messages in the mailbox using the Write Message command (AAh).
Please note that the VCC poser must be present in order to write into the mailbox (MB_EN=1 can't be written if VCC is not present).

Best regards.

[YazTarkann]

When I read the FTM configuration (02A0020D) I get: 0001, so the FTM is activated.
For the mailBox, the “ST25 NFC TAP” application tells me in the Mailbox Management tab: Mailbox enabled.
The command: 02AE020D01 returns 00.

For the AA command, I can't get anything other than “0102” in response. Could you give me an example of a frame with the command “35FF1234EEEEEEEEEE40FFFFFFFF0000” please?

[YazTarkann]

Can someone help me for this ?

[JL. Lebon]

Hello, 

The command AA is the Write Message command. It will return only a status, not data. It is used to write some data into the mailbox.
What do you mean by command "35FF1234EEEEEEEEEE40FFFFFFFF0000". Is it the data you want to write into the mailbox?
Do you want to read something from the mailbox ?

Best regards.

[YazTarkann]

Hello,

The command : "35FF1234EEEEEEEEEE40FFFFFFFF0000" is to unlock a connected padLock, the device can send back an answer but the first step is to unlock the padlock with this command.

[YazTarkann]

Can someone help me ?

[JL. Lebon]

Hello, 

Can you please explain more your problem.
It is not clear to me what the "padlock" is and what the "35FF1234EEEEEEEEEE40FFFFFFFF0000" command is.
This does not look like an NFC type 5 command.
Is it a payload that you want to send to a MCU through the ST25DV mailbox?

Best regards.

[YazTarkann]

Simply put, the padlock is a connected object (IoT). And the command “35FF123EEEEEEEEEE40FFFFFFFF0000” is a product-specific command. With a specialized application (IoTize, a French company) it is possible to send this command to the product, which performs an action in return (opening a jaw to release a cable).
Unfortunately I don't have access to the source code, so I can't work out how this command is encapsulated to be interpreted by the NFC module.
I know I need to write this command to the mailbox, but how do I write to the mailbox

[JL. Lebon · Accepted solution]

Hello, 

To write this "padlock" command into the mailbox, you need to

1. authorize the mailbox: write MB_MODE=1 in FTM configuration (Write configuration command)
2. enable the mailbox: write MB_EN=1 in MB_CTRL_Dyn regsiter (Write Register command)
3. write your "padlock" message in the mailbox using the Write message command.
At this point, the message is in the mailbox and must can read by the microcontroller on the I2C interface. If you don't have access to the microcontroller FW source code, you will probably not be able to go any further.

You can read those post to better understand how mailbox works:
Write on Mailbox via Android APP (ST25DV64KC) - STMicroelectronics Community
Solved: Re: STM32 ST25DV library - STMicroelectronics Community

Best regards.