Read_message_length and other read configuration commands returns 00 01 value.

[YBhat.1]

Hi,

I am using ST25DV04 discovery kit.

I have used the GUI menu on the Kit to put the Tag in FTM mode to transfer picture.

I am using another reader to read the picture.

The flow I am following is as follows:

• Discover the NFC IC.
• Ask the IC for message length using ABh command.

I am of impression that as the NFC Tag is already ready for FTM I should not need to make any other configurations. Am I correct in making that assumption?

It is also worth nothing that the read operation does not return any error flag and that makes the returned value 00 01.

But the problem is that this does not seem right as other Read Configuration commands (0xA0) for GPO, MB_WDG, MB_MODE also return the same behavior i.e 00 01.

After presenting the system default password of 00 00 00 00 00 00 00 00,

I have tried first updating the register with new value and then reading back, both of which dont report an error but upon read back the register value remains unchanged.

Please help me out with this.

Thanks

[Rene Lenerve · Accepted solution]

Hi @YBhat.1​ ,

> I am of impression that as the NFC Tag is already ready for FTM I should not need to make any other configurations. Am I correct in making that assumption?

Yes you are right, once you have entered the Fast Transfer Mode menu, the discovery is waiting to receive Fast Transfer Mode frames.

> It is also worth nothing that the read operation does not return any error flag and that makes the returned value 00 01.

> But the problem is that this does not seem right as other Read Configuration commands (0xA0) for GPO, MB_WDG, MB_MODE also return the same behavior i.e 00 01.

Which reader are you using for these commands? And which software do you use?

Can you try with other configuration in the request flag? 01 => Two subcarriers, 02 => High data rate, 03 ...

Hope this can help

Best Regards.