How to access ST25DV registers on iOS using React Native if NfcV is not supported?

[shahbaz]

I am working on a React Native project for an NFC app that needs to run on both iOS and Android. I am using the react-native-nfc-manager library to perform NFC operations. The NFC tag I am using is ST25DV, which supports NDEF and NfcV (ISO15693) technologies.

In my app, I need to perform:

• Writing different types of NDEF messages (URI, AAR, etc.).
• Writing directly to static registers (e.g., RFA1SS, ENDA1, RF_PWD_1, etc.).

For writing to registers, I need to access raw memory blocks, which requires NfcV commands.

According to the react-native-nfc-manager documentation, NfcV is not supported on iOS. That leaves me only with NDEF, as the tag only supports NDEF and NfcV.

My questions:

• Is there any way to access or write to those registers on iOS without NfcV?

• Is there a workaround to enable or simulate NfcV support on iOS?

• Or am I limited to NDEF-only operations on iOS with this tag?

Here’s a snippet from my current code that uses NfcV to write a static register (works on Android) I haven't tested that code on iOS yet (as I haven't setup React Native on mac yet for iOS development)

```

await NfcManager.requestTechnology(NfcTech.NfcV);
const tag = await NfcManager.getTag();

const res = awaitr NfcManager.transceive([
0x02, // Request Flag
0xA1, // Command Code for Write Config Register
0x02, // IC Mfg Code fot ST25DV
0x09, // Pointer Address of ENDA1 register
0x3F, // Value of ENDA1
]);

```

[Ulysses HERNIOSUS]

Hi,

on community there was some time back another post on react native. Maybe it helps:

https://community.st.com/t5/st25-nfc-rfid-tags-and-readers/configuration-security-session-via-rf-not-working/m-p/727556

BR, Ulysses

[victor laraison]

Hi,

On iOS, Apple’s Core NFC framework supports reading and writing NDEF messages and ISO15693 tags, but does not expose low-level transceive commands for NfcV (ISO15693). This means you cannot send custom raw commands to the tag registers like you do on Android.

If you want to perform operations equivalent to raw transceive commands on iOS, you need to use the dedicated ISO15693 command methods provided by Core NFC (and exposed in react-native-nfc-manager if supported). These include commands like:

• readSingleBlock
• readMultipleBlocks
• writeSingleBlock
• getSystemInfo
• stayQuiet
• select
• resetToReady
• etc.

So , you must  "wrap" raw transceive commands into every iOS ISO15693 Core NFC commands.
you must translate your required operation into one or more of the standard ISO15693 commands supported by iOS.

Hope it helps,

Br